Koninklijk Nederlands Indisch Leger (KNIL Army): Lieutenant-General Hein Ter Poorten 16th Army: General Hitoshi Imamura[5] The Japanese forces were split into two groups: the Eastern Force, with its headquarters at Jolo Island in the Sulu Archipelago, included the 48th Division and the 56th Regimental Group.

Blackburn managed to assemble an HQ staff and three infantry battalions based on the 2/3rd Machine Gun, the 2/2nd Pioneers, and a mixed "Reserve Group".

The convoy left Cam Ranh Bay at 10:00 on 18 February, and the commander-in-chief Lieutenant General Hitoshi Imamura was aboard on the transport ship Ryujo Maru.

Ten minutes later they were joined by the other transport ships; the one carrying the Sato detachment dropped anchor at Bantam Bay.

They found many of the bridges already destroyed by the retreating Dutch and were forced to find other routes; some units took the opportunity to make for Buitenzorg.

On 27 February, the unit 3rd mixed Regiment, led by Colonel Toshishige Shoji, separated from the main convoy and landed on 1 March, at Eretan Wetan, near Soebang on the northern coast of West Java.

The unit's objectives were to capture the important Kalidjati airfield and weaken the Allied air arm, while the 2nd Division attacked Batavia.

Meanwhile, other Japanese units led by Major Masaru Egashira bypassed Allied defences and headed for Pamanoekan (Pamanukan), and from then on to Cikampek (Tjikampek), where they were able to cut the road link between Batavia and Kalidjati.

At 10:00 on 8 March, Major-General Jacob J. Pesman, the commander of Stafgroep Bandoeng,[14] met Colonel Toshishige Shoji at the Isola Hotel in Lembang and surrendered.

The Japanese won the battle and at 00:15 on 1 March, the fleet landed in Kragan, a small village in East Java, approximately 100 mi (160 km) west of Surabaya.

The Japanese proceeded further and overwhelmed the Dutch defences at the Ngawi Regency, Tjaroeban (Caruban), Ngandjoek, Kertosono, Kediri and Djombang.

At Porong, near Surabaya, the Dutch infantry from 8th, 13th Battalion, 3rd Cavalry Unit and the American 131st (Texas) "E" Field Artillery Regiment gave fierce resistance to the incoming Japanese.

Eventually, the Allied troops under Major-General Gustav A. Ilgen had to retreat to the island of Madura upon the completion of demolition of the city's infrastructure.

In one week, they advanced rapidly and overcame all Dutch army defence found in Blora, Soerakarta, Bojolali, Djokjakarta, Magelang, Salatiga, Ambarawa and Poerworedjo.

On the following day, Major-General Pierre A. Cox – the Dutch Central Army District commander – surrendered his troops to the Japanese.

At 09:00 on 8 March, the Commander-in-Chief of the Allied forces – Ter Poorten – announced the surrender of the Royal Netherlands East Indies Army in Java.

On 3 March, the U.S. Navy gunboat USS Asheville was sunk south of Java by a Japanese naval squadron consisting of the destroyers Arashi and Nowaki, and the heavy cruiser Maya.

[20] On 10 March, Lieutenant-General Hitoshi Imamura became the new governor of Java and Madura, thus becoming the highest authority in the occupied Dutch East Indies.

Imamura was subordinated to Field Marshal Count Hisaichi Terauchi, the Supreme Commander of the Southern Army, headquartered in Saigon, French Indochina.

He was also the governor of the so-called "Southern Territories" (Malaya, Burma, the Philippines, Hong Kong, Java, Sumatra, and Borneo) and directly subordinated to the Imperial Headquarters in Tokyo, Japan.

On 12 March, the senior British, Australian and American commanders were summoned to Bandoeng where the formal instrument of surrender was signed in the presence of the Japanese commander in the Bandoeng area, Lieutenant-General Masao Maruyama, who promised them the rights of the Geneva Convention for the protection of prisoners of war.

Because the Allied naval force had been destroyed, the Indian Ocean and the approach to Australia lay open to the Imperial Japanese Navy.