Battle of Manado


The Battle of Manado took place as part of the Japanese offensive to capture the Dutch East Indies. It occurred at Manado on the Minahasa Peninsula on the northern part of Celebes Island, from 11–12 January 1942. The battle was noted as the first time in Japanese history that the country had deployed paratroopers in a military operation.

Background

Minahasa's strategic value

Even though the Minahasa Peninsula does not contain any raw materials or strategic technical installations, its military value remained essential. The sheltered bays of Manado and Lake Tondano provide good bases for seaplanes, as Dutch forces established a Naval Base on the southeast side of Tondano Lake, near Tasoeka. A seaplane base was also established on the southern part of the Lake, near Kakas.
Aside from that, Dutch forces also constructed two airfields nearby. At the Kalawiran village near Langoan, the Menado II/Langoan Airfield was established. When the war broke out, Manado I Airfield, located just east of Manado City at Mapanget was still under construction.

Japanese invasion plan

As part of the Japan's plan to conquer the Netherlands East Indies, particularly the island of Java, air support from southern Sumatra, Kuching, Banjarmasin, Makassar and Kendari was required. Beforehand, however, in order to set up the aforementioned aerial support, specifically in southern Celebes and Banjarmasin, relay fields in Manado, Tarakan and Balikpapan had to be conquered as well.
The seizure of Manado was outlined as part of Japan's Eastern Offensive prong to capture the Dutch East Indies. Responsilibility for conducting attacks on this prong falls to the Imperial Japanese Navy.

Order of battle

Japan

Ground forces

Eastern Attack Unit :
Air Group
2nd Air Unit :
Base Force :
1st Base Unit:

Ground forces

Troepencommando Menado of ca. 1,500 infantry :
Artillery:
The Dutch defense plan for Manado consists of:
Between May 1940 and December 1941, the Dutch forces in Manado made necessary defense preparation. These preparations consisted of establishing several monitoring services, to which 2 Reserve Corps companies were assigned to conduct these services. In addition, the Dutch also worked to construct several defensive positions. However, due to limited funding, few of these positions were completed by the time the Pacific war broke out.
By 8 December 1941, Schillmöller arranged his troops to be stationed in these positions:
For the defense of Langoan airfield and Kakas Seaplane Base, Schillmöller established the Tactical Command Kakas, under the command of Captain W.C. van den Berg. Van den Berg had the available forces at his disposal:
Finally, to accommodate the guerrilla plan, nine underground warehouses were built to store supplies that will be needed during the action. Remaining Dutch troops will be divided into six sections, where each were assigned to a specific warehouse. The sections are:
  1. Compagnie Menado with European Militia
  2. KV Company with E-Company RK
  3. A company RK
  4. B-company RK
  5. C-company RK.
  6. D-company RK.

    Japanese plans

The Eastern Attack Unit was assigned as the Japanese fleet tasked with capturing Menado. Eventhough Rear-Adm. Takeo Takagi commanded this force, he left the operation details to Rear-Adm. Raizō Tanaka. The battle plan intends for the Sasebo Combined Landing Force, as well as the Yokosuka 1st Special Naval Landing Force as a paratrooper unit.

Sasebo Combined Special Landing Force

The Sasebo Combined Special Landing Force's mission for the upcoming battle consisted of:
The Sasebo Force will depart Davao on 9 January, and the land in the early hours of the 11th.

1st Yokosuka Special Naval Landing Force (SNLF)

The 1st Yokosuka SNLF, in conjunction with the Sasebo Force, will carry out a paradrop operation on the enemy airfield at 09:30 A.M. on 11 January with the support of the fighters of the 1st Air Raid Unit. Their objectives are to seize Langoan airfield and the Kakas Seaplane Base, two facilities that will support subsequent Japanese operations for the Dutch East Indies campaign.
The distribution of tasks and actions of each unit, are:
DistributionNo. of personnelMission
1st Drop Group334 paratroopers
Carry out a paradrop on the Langoan airfield on 11 January. Afterwards, the group will be split into two forces:
1. 1st Company will capture the airfield.
2. The 2nd Company and the rest of the force will seize the Kakas seaplane base
2nd Drop Group173 paratroopersCarry out a paradrop on the Langoan airfield on 12 January
Kema Unit169 soldiersLeave Davao on the Katsuragi Maru on 6 January.
Upon landing in Kema, they will transport war supplies, before joining the main body.
Tondano Lake Unit22 soldiers
Leave Davao on 11 January on Kawanishi H6K "Mavis" flying boats.
On landing in Lake Tondano, they will join the main body and receive orders.
Menado Unit64 soldiersLeave Davao as separately designated, and transport war supplies.
Afterwards, they will join the main body and receive orders.

The Mitsubishi G3M transport aircraft of the 1st Yokosuka SNLF would fly with an interval of between each company. Carrying 12 paras and seven cargo containers each, 10 planes will carry the 1st Drop Group, while 8 will carry the 2nd Group. The drops would occur at an altitude of and at a speed of.

The battle

Landing on Manado (1st Force)

Following the sighting of Japanese transport ships on 10 January, Schillmöller immediately garrisoned the troops in their quarters as planned. He also ordered Capt. Kroon's Combined Force to occupy the Manado coastlines and guard it against possible landings. On Kroon's left flank, in the Sario District, he placed Masselink's European Militia, while Lt. de Man's Stadswacht dig in on the right. Engineers are placed on standby, waiting for the order to destroy vital installations; NCOs and members of local government were also informed of the looming Japanese landing.
Mori's 1st Sasebo Force landed on the northern and southern coast of Manado at 04:00 A.M on 11 January. Upon hearing reports about the landing, Kroon's Compagnie Menado immediately withdrew to the rear positions at Pineleng and Tinoör, without knowing what is happening on the beach, as Mori's troops overrun the 75 mm gun that was firing at the landing boats. Yet they also ran into stout opposition from Masselink's militias, forcing them to bring all their automatic fire to bear. Japanese pressure forced Masselink to withdraw to Pineleng, only to find that the 1st Force had bypassed them into the town at 05:00, pressing him to move further southward.
When Kroon's troops arrived half an hour later, Mori's troops forced him to withdraw southward along the Manado-Tomohon road to Roeroekan. When Masselink reported his positions to Schillmöller, he ordered him occupy the bridge at Pineleng instead, even though Japanese troops had already occupied it. Masselink eventually continued the retreat, reaching Tinoör by 07:00. After battling the Combined Force, Mori's 1st Force occupied Manado by 08:30. As reports of the landing began to come in, Schillmöller sent 5 RK brigades under Lt. van de Laar in Tomohon to Tinoör to support the retreating Combined Force. Immediately after capturing Manado, Mori advance southward to Tomohon at 09:45, bypassing the Dutch line of retreat.
Soon, Schillmöller pulled three brigades from van de Laar's force back to Tomohon to reinforce the town against a false intelligence about Japanese landing in Tanahwangko, further west of Manado. Despite this withdrawal, van de Laar was reinforced by stragglers from Compagnie Menado and an overvalwagen as well as Stadswacht troops under Lt. de Man. To provide protection against Japanese tanks, Dutch troops swiftly cut down a heavy tree that will fall on the road the moment the tanks came. As Mori's vanguard of four Type 95 tanks approached the town at 10:30, the falling tree and concentrated machine gun fire knocked out three of them and repel Mori's troops. van de Laar's troops hold on to Tinoor until about noon, when the shortage of ammunition forced them back to Kakaskasen.
Now supported by overvalwagens, van de Laar set up a new defensive position just north of Kakaskasen.1st Force engaged them again at 16:00, but Dutch troops managed to stem their advance and caused substantial casualties before retreating again. Yet, since Mori continues to bypass them, once the Dutch arrived in Tomohon, they found themselves immediately fighting the 1st Force's. The Combined Force attempted a defense against the Japanese advance, but they could not stop Mori from seizing Tomohon by 19:30. van de Laar's troops moved eastwards to Roeroekan, arriving at 22:00. By morning of the 12th, Mori advanced to Langoan Airfield by way of Tomohon to Kawangkoan. By 12:30, his troops established contact with the 1st Yokosuka paras and arrived at Langoan and Kakas at 14:00. Dutch forces had, by then, retreated to Amoerang further west, while blowing up bridges and warehouses, making no attempts of counterattack in the meantime.

Landing on Kema (2nd Force)

Lt. Radema's A Company, tasked with defending the eastern coast, was spread in the road between the coastal city of Kema and Ajermadidih. In addition to the brigades at both aforementioned cities, three brigades were stationed at Mapanget Airfield, and one brigade each were stationed in Likoepang and Bitoeng, further north from Kema. Radema also constructed machine gun casemates and tank barricades along the road from Kema to Ajermadidih.
At the same time with the 1st Force landing, Commander Uroku Hashimoto 's 2nd Sasebo Force landed at Kema on the east at 04:20 and engaged Radema's two brigades. When notified about the Landing, Radema ordered the dispersed A-Company to gather at Ajermadidih, but only the troops from Likoepang eventually came. Meanwhile at Kema, the two brigade under Sgt. Soenda retreated after destroying the town bridge; Hashimoto spared no time continued to advance to Ajermadidih. Near Kasar the brigades clashed with the 2nd Force and had to withdraw again after inflicting modest casualties.
By 09:00, the 2nd Force, supported by three Type 95 tanks, advanced to the east of Ajermadidih and engaged Radema's Company, now reinforced with its remaining brigades. Even though Radema's troops managed to caused considerable casualties, Japanese tanks eventually broke through and threatened to outflank the Dutch defense, forcing Radema to retreat by 14:00. To cover their withdraw, Sgt. Roemambi and Pvt. Iniray and Poesoeng continued to fire from their casemate until it was destroyed by tank shells.
Another cover force of a brigade under Sgt. Sigar hold Hashimoto's troops at Sawangan to allow Radema safe passage to Tondano. After driving Sigar's brigade back through force majeure and airplane attacks, an element of the 2nd Force reached Tondano by 18:00, and by 22:00, Hashimoto had reached the town and halted there for the night. By morning on the 12th, Hashimoto went along the road the eastern and western shores of lake Tondano, linking up with the 1st Yokosuka paras by 11:00 and the 1st Sasebo Force at 12:30. By the night of the 11th, however, Schillmöller had decided to withdraw to the west and commenced a guerilla fight.
Radema left with about 12 troops to the warehouse allocated for his company, but soldiers began to desert along the way. When he arrived of the shelter, it had already been looted by the local population, forcing him to try to infiltrate Ajermadidih to gather what is left of his forces. The rest of his troops eventually abandoned him as well during the journey. The high rate of desertion was exacerbated by the fact that the Japanese have taken hold all major cities and towns – and therefore women and children – within 24 hours. In addition, Japanese forces also dropped out pamphlets that read: "The war is not going on against you, only against the Dutch. So be sensible, don't interfere and go home."

Airborne drop

On the night of 10-11 January, the Kakas Command Post was alerted by Tomohon, compelling van den Berg to send motorcycle messengers to place his troops on high alert. When Tomohon informed him again at 05:00 of the Japanese landing in Manado and Kema, a brigade from the reserve KV section at Kakas moved to Papakelan to close the roads leading to Tondano.
Concurrently, at 06:30 A.M. on 11 January, 28 Mitsubishi G3M left Davao for Manado, carrying the 1st Drop Group with them. While the flight approached northern Celebes, a group of Mitsubishi F1M "Pete" that was covering the naval invasion force mistakenly attacked them, shooting down a G3M and killing all 12 paras aboard. To prevent further friendly fire incident, Mitsubishi Zero fighters from the carrier Zuiho escorted the flight until it reached the drop zone. In due course, the 1st Group began dropping over Langoan at 09:52 and completed the drop by 10:20. Van den Berg immediately ordered the rest of the reserve KV section to take position west of Kakas to defend against another possible landing. He wanted to call in the reserve KV section in Langoan as well, but Schillmöller had already used them.
Robbemond's troops, though lacking in anti-aircraft guns, used their Vickers and Madsen machine guns to open fire into the paras and repel the oncoming assault. Several paras were dropped close to Dutch pillboxes, and they had to destroy them with pistols and hand grenades, while giving time for the rest of the group to gather weapons from the cargo container.
Upon retrieving their weapons, Horiuchi focused the attack against Robbemond's troops on the northern side of the airfield. By 10:50, the paras had enveloped the northern side, capturing the overvalwagen with it. Schillmöller then put in the reserve KV Company section in Kakas into the battle. The Company was ordered to advance to Toelian and reinforce Van den Berg's troops at the airfield. However the order was not carried out, as the unit disappeared with no further notification. Van den Berg then ordered the two overvalwagens on reserve under ter Voert to attack the airfield. Entering the vicinity of Langoan under heavy fire, one overvalwagen had its engine shot off. Its gunners, Pvt.Tauran and Pvt. Toemoedi kept firing their machine guns to provide cover for rest of the crew, before retreating in the face of the advancing paras. The second one, under Sgt. Bojoh, entered the airfield and took part in the battle before eventually withdrawing.
In spite of the dogged resistance, the 1st Drop Group overran the airfield by 11:25. As the battle progresses, Van den Berg called Lt. Fuchter's Company, along with the Mobile Colonne to attack the paras from a westerly direction, via Panasen. Yet Fuchter did not arrive at Kakas until 11:30, where by then Langoan Airfield had already been lost, thus cancelling the attack. Van den Berg then ordered Fuchter's Company and the Mobile Colonne to take position to the south and west of Kakas and relieve the Militia-Landstorm Company stationed there. Upon accessing the number of casualties sustained and the very few troops that were still able to fight, van den Berg's troops destroyed the Tasoeka Naval Base and prepare his troops to move into their assigned guerrilla territory.
At 12:35 van den Berg informed Tomohon that he was leaving for the area east of Tasoeka. He sent the Militia-Landstorm Company – deemed unfit for a guerrilla fight – westwards to Kotamobagoe to join forces with the Manado Militia Company. Lt. Wielinga, the overall commander of the airfield defense, did not use his brigade to support the battle, and had already retreated during the battle instead.
Upon capturing the airfield, Horiuchi sent a reconnaissance team moved to the Kakas area at 13:00 to reconnoiter Dutch movement. Ter Voert, Tauran and Toemoedi who just reached Kakas on foot immediately reported the movement. The team encountered and captured an overvalwagen before moving into Kakas, where they engaged another overvalwagen and forced it to withdraw. 1st and 2nd Company, advancing towards Kakas, engaged with Fuchter's Company, which was supported by an overvalwagen. After an extensive fight, the paras drove Fuchter's troops off and seized Kakas by 14:50. At 15:50 the paras attacked the seaplane base and captured it by 18:00. The attack was supported by the Tondano Lake Unit, who landed by two Mavis flying boats on Tondano Lake at 14:57. While landing, the Unit came under fire from Mobile Colonne's 37 mm guns, which was not sufficient to halt the process.
The following day, the 2nd Drop Group parachuted into Langoan airfield at 09:52 A.M. and linked up with the 1st Drop Group. Horiuchi's force, in full capacity, launched an assault on Langoan city and the neighboring Tompaso. By then, Schillmöller had withdrawn westward, towards Amoerang, leaving behind large amounts of weapon and ammunition. Langoan was captured by 11:25, with Tompaso following suit at 12:30. Another element of the paras advanced to Paso and seized the city at 10:35. By 14:00, Horiuchi managed to link up with both 1st and 2nd Sasebo Force.

Aftermath

From 13 January, the Sasebo Combined Special Landing Force conducted a mopping-up operation of Manado and its vicinity. They completed the operation on the 16th, and assembled in Menado to start preparations for the capture of Kendari. The 1st Yokosuka SNLF, on the other hand, continued to be stationed at the Langoan Airfield until 24 April, when they were assigned in small groups to attack nearby islands on landing crafts. The force reassembled at Makassar in November 1942 to be transported back to Japan.

Casualties

Japanese casualties from the battle are as follows:
  • 1st Yokosuka Special Naval Landing Force : 32 killed, ca. 90 wounded
  • Sasebo Combined Special Landing Force: 12 killed, 154 wounded
140 Dutch troops were killed in the battle, with another 48 captured. The Japanese also captured ten 8-mm field guns and a significant number of machineguns, rifles, and other supplies.

Reprisals

In retaliation for the high number of casualties, Horiuchi's paras executed Dutch POW's defending the airfield. Lt. Wielinga was captured in Gorontalo and taken to Langoan, where he was beheaded on 1 March. In addition, the paras also beheaded or bayonetted: Sgt. Robbemond, Sgt. B. Visscher, Pvt. Toemedi and nine Menadonese soldiers. Another two Menadonese soldiers died from torture in captivity.

The guerrilla war

On the night of 11 January in Roeroekan, when the Dutch decided to commence their guerrila war, Schilmöller gave money to three of his commanders – captains Kroon and Abbink and lieutenant Van de Laar – and ordered them to begin the guerrilla fighting in their respective regions. Minahasa's geography of open terrain, however, makes it difficult to stage a guerilla fighting. Furthermore, some of the underground warehouses had already been looted by the local population, which adds to the crucial question of supplying the troops.

Schilmoller's Group

Schilmöller himself planned to set up his base in Lake Tondano and established contact with any unlocated units from there. With three brigades from RK's B-Company, he moved to the area between Lake Tondano and the Lembean Mountains. Yet when his only radio broke down, Schilmöller marched his group westwards to Kotamobagoe, where the Menadonese Militia Company was located, to establish communication with KNIL Headquarter based in Java. On 20 January, his group made contact with Capt. Van den Berg's group just southeast of Lake Tondano. The latter suggested that he left B-Company behind and take the elderly and the physically weak to Kotamobagoe. Instead, Schilmöller, kept B-Company and reinforced it with Capt. Van den Berg's best troops.
The next day, the former's group left for Pasolo on the east coast, where from there they will steam south as far as possible. When the group reached Pasolo, however, the insufficient amount of water transport means that they could not depart in one go. Half of the group, including Sgt. Chief of Staff J.F. Flips, were left under the command of 1st Lt. Siegmund and will be picked up later. But before it could happened, the Japanese overran and captured the group. After being subjected to extensive torture, Siegmund and Flips were executed in Langoan on 27 January.
Schillmöller arrived in Kotamobagoe on 26 January, where he was able reestablish radio communication and reported his conditions to the Dutch General Headquarters in Java. On 31 January, the Headquarters ordered Schillmöller to make his way to Makassar, where from there he will be transported back to Java. Under pressure from Japanese propaganda which could spark local uprising, Schillmöller decided to bring his group to Poso, in Central Celebes. However, the Dutch were not able to acquire sea transport until 26 February, at which point Makassar had already fallen into Japanese hands for over two weeks.
With few options remaining, Schillmöller decided to continue to wage guerrilla warfare in Central Celebes, bolstering his group with Dutch detachments from Poso, Paloe and Kolonedale. First to join was Lt. Willem van Daalen and his 60 troops; another two detachments joined in from Poso, one under the command of Lt. Johannes de Jong. Despite the increasing number, most of the troops are lightly armed, and some of them have no training at all. Furthermore, there's also the consideration that the local population could not be expected to provide support in continuing the fight. Eventually, when he heard the news of Dutch surrender at Java on 8 March, Schillmöller decided to capitulate.

Kroon's Group

On 12 January, Captain Kroon and the remainder 50 troops his company left Roeroekan and headed northward to Kembes. The high rate of desertion by Menadonese soldiers left Kroon with only 9 men, when Japanese troops captured his group and take them to Kembes, before eventually transporting them to Manado. On 26 January, a day after they arrived, all European soldiers - except Captain Kroon - were executed. Those executed included 4 NCOs and 2 Militia-Landstorm soldiers.

Abbink-Masselink's Group

Capt. Abbink's group headed southwest to start their guerrilla fighting in the Amoerang area, yet the similar wave of desertion left him with only four soldiers. Hoping to connect with other guerrilla forces, Abbink traveled from 17 January to 1 February, when his group met with 8 RK soldiers under Lt. Masselink at northeast of Amoerang. After the battle in Tinoör, Masselink and Sgt. Siwy arrived in Kakaskasen and attempted to reach the command post in Tomohon. Yet when they heard that Japanese troops had occupied the city, their guerrilla warfare had already begun.
On 13 or 14 January Masselink's group met up with 27 former soldiers who had retreated from Tanahwangko. As they began preparing for the guerrilla fighting, the high desertion rate had shrunk Masselink's group to 5 troops. The Abbink / Masselink group soon learned of the Dutch forces' surrender in Manado and lost contact with Schillmöller's group. These factors led them to leave for the safety of Kotamobagoe, where they raided supplies and arms from the local police. After arriving at the Manado Milita Company barracks on 9 February, they left for Poso in Central Celebes.

Meliëzer's Group

On 11 January, Sgt. Johan Meliëzer's E-Detachment was stationed at Amoerang when it came under fire from Japanese ships, killing one and injuring three. Having lost contact with Tomohon, Meliëzer sent a motorcycle messenger to Maj. Schilmöller, who ordered the Detachment to reinforce the troops at Langoan Airfield. Making the advance under constant fear of air raid, E-Detachment's 20 troops arrived at the airfield on 12 January, only to find that Japanese troops already occupied it. E-Detachment's troops immediately dispersed and returned home, with many feared to take up arms again for the guerilla fighting.
Nevertheless, Maliëzer refused to capitulate and began organizing a guerrilla group of approximately 15 troops in the second half of January. The group is also joined by civilians, among them Mrs. Hoffman, the spouse of a retired MWO Knight who was executed for aiding Dutch guerrilla troops. On 8 February, the group repulsed a day-long Japanese attack at Kanejan, just east of Toempaän. In reprisal for their loss at Kanejan, Japanese troops burned down a kampong and beheaded five civilians, including two women. In another battle just four days later, they captured Meliëzer's group and brought them to Langoan. After a short time in captivity, Maliëzer was beheaded in Langoan on 20 February, along with 12 other members of his group, among them Mrs. Hoffman.

van den Berg's Group

From Tasoeka, Capt. van den Berg's group make camp on the slopes of the Lembean mountains on the night of 11 January. A steady stream of troops joining in turns his group into a 101-strong force just three days later. van den Berg divided them into four brigades of 22 soldiers each, along with a staff group of 13 troops and nurses. Two of the brigades were commanded by Fuchter, while Sgt. Maj. Ranti commanded the other two and Ter Voert commanded the staff group.
On 17 January in Karor, naval personnels from Kema, under the command of 2nd Lt. W.A. de Ruiter, joined the group. Three days later, they met with Schilmöller's group, just north of Kajoe Watoe. As mentioned, Schilmöller deprived the group of most of its fighting force, leaving van den Berg with just 23 troops left that will gather other dispersed troops in the region, thus diminishing the capacity to wage guerrilla in Minahasa.
During the encounter with Schilmöller, Fuchter's brigades have been on patrol for 5 days, when they encountered a Japanese motorcade in a chaotic nightime fighting that left Fuchter with just 10 soldiers at its conclusion. By the night of 22 January, Japanese troops raided his barracks at Kombi and captured his entire group. Ranti's brigades, who was deployed to the southeastern side of Lake Tondano on 15 January, returned from the patrol on 20 January. Half of them, however, decided to continue the guerrilla in Kaweng.
On 4 on February, the group at Kaweng fought off a Japanese attack that killed three of their soldiers, for the unconfirmed loss of 37 Japanese troops. Meanwhile, van den Berg's group - amounting to just 1 brigade - continues to maintain itself in Lembean mountains for the time being and carried out demolition works. The group also continued to gather any soldier in an attempt to carry out a large-scale raid on Langoan Airfield or Tondano.
Before this endeavor could be conducted, 60-80 Japanese troops – aided by the local population – encircled van den Berg's base just southwest of Kasar on 17 February. Realizing that a daylight outbreak could not be successful, the group attempted to escape from the barracks at night. One by one, and under cover of darkness, soldiers from the group left the barracks, with Capt. van den Berg being the last person to leave. Despite the success of the escape, the involvement of the local population on the Japanese side meant that the situation for the group was becoming more untenable.
By 20 February, leaving the sick and elderly behind, the group moved to the mouth of Kali Rakar, where they began the trek south along the coast using wooden boats. After rowing for 14 hours, the brigade reached Pasir Poetih, ca. 80 km south of Kali Rakar. A local fisherman quickly notified their presence to the Japanese, who swiftly surrounded the coast. The group managed to flee once more, but was captured on 22 February, a day after they had come ashore. Admiring their persistent resistance and heroic stand, the Japanese War Council in Langoan spared Van den Berg's group from execution. After the war, van den Berg was made Knight Commander of the Militaire Williams-Orde, 4th Class.

de Jong & van Daalen's Group

On 12 March, Schillmöller sent one of his officer to Manado to discuss the terms of surrender with the Japanese. He had hoped that his troops would be allowed to keep their weapons, to maintain order and protect the European civil servants and families that have been travelling along with the group. Instead, the Japanese demanded that the Dutch surrender all their weapons and for all members of the group to make their way to Manado. Schillmöller left the group for Manado on 23 March, while a detachment of 50 Japanese soldiers was sent to Poso to bring his group back to Manado. De Jong and van Daalen, however, rejected the demand to surrender their weapons and turned back on their decision to capitulate. When the Japanese detachment arrived in April, the Dutch opened fire at them, killing the detachment commander and wounding others.
In May, the Japanese sent a 400-strong unit to engage the Dutch guerrilla force of 125 soldiers who withdrew and continued their fight inland. De Jong and van Daalen created two groups and based themselves each in the east of Poso and around Kolonedale respectively. On 9-10 June, de Jong's group came upon a National Administration's radio station in Kolonedale and establish contact with Dutch representatives in Australia, requesting food, weapons and ammunition. Unbeknownst to them, Japanese forces managed to intercept the radio communication.
Responding to the newly-established contact, a "party" was created in Australia, whose task is to infiltrate Celebes and came back with intelligence or conduct sabotage operation. Named Lion, the party consisted of engineer Robert Hees, telegraphist Bernard Belloni and marine engineer Hans Brandon. Lion party left the port on the boat Samoa on 24 June and landed in Wotoe, south of Kolonedale, after a 1,700-kilometer journey. Local population immediately reported their presence to the Japanese, who captured all three after a firefight on 12-13 July. After a period of captivity and torture, the Japanese beheaded them in Makassar on 14 September.Even as the Japanese continue to add pressure on both guerrilla groups, in conjunction with increasing desertion and casualties, both groups continued to exert casualties on the Japanese force. Before July, the group had killed around 100 Japanese soldiers, at a loss of three killed and four captured. On 7 July, de Jong's troops attacked Japanese forces in Salenda. The Japanese came in three vehicles and were equipped with automatic weapons and mortars. A heavy firefight ensued until 21:00 on the 7th, and continued again to 06:00–09:00 the next day. At the end of it, seven Japanese officers and between 35-70 Japanese soldiers had been killed. Witnesses stated that all three vehicles were astrewn with Japanese bodies, which were then burned with gasoline.
It was not until 15 July for the supplies to be delivered from Australia. At that point, the Japanese had already landed at Kolonedale, destroyed the radio station and captured the supply drops. At the same time, local residents had been recruited to aid the search for the Dutch guerrillas. The Japanese finally captured de Jong and van Daalen on 9 August 1942. Both officers were imprisoned at Kolonedale, before transferred to Manado. After extended interrogation and torture, de Jong and van Daalen were beheaded on 25 August. Along with them, the Japanese also beheaded 15 soldiers from the guerrila group. Earlier on 13 August, 9 soldiers had also been executed.
Hegener argued de Jong and van Daalen's guerrilla actions had been quite effective due to Minahasa's natural suitability and the Japanese's lack of experience in dealing with guerrilla warfare. The group had initial hit-and-run successes, but as the local population's support for the Japanese grew and more troops were being allocated to fight them, the effectiveness of the guerrilla war eventually dwindled away. After the war, de Jong was made Knight Commander of the Militaire Williams-Orde, 4th Class and van Daalen received the Bronze Lion, both posthumously.

Liberation

Menado remained under Japanese occupation until October 1945, when the Australian-composed "Menado Force" liberated the region.