After a brief stop in retrieving the mines from Singapore in early 1941, the minelayer HNLMS Willem van der Zaan of the Zeemacht Nederlands-Indië (Royal Dutch Navy) was deployed to Riau in April.

[3] In 1 January 1942, the Dutch shallop HNLMS Soemba, equipped as a gunboat, was stationed in the Riau archipelago for some time under Commander P. J. G. Huyer.

[5] Japanese air forces targeted Allied and Dutch warships traversing the Strait of Malacca as part of their broader strategy to dominate Southeast Asia.

Tarempa, located on the island of Matak, became a focal point of Japan’s campaign to seize control of the south due to its strategic importance as a Dutch defense base.

The city housed a critical radio station and a makeshift airport vital for Dutch military communications, making it a priority target.

Despite prior enemy air activity in the area, little attention was initially paid to their approach until the bombers descended to a low altitude and opened their bomb bay doors.

Berlijn gave the order to abandon ship, though the forward gun crew continued firing in an attempt to force the bombers to ascend to a higher altitude.

van Casand, boarded a motorboat and made multiple trips between HNLMS Deneb and the Martha, rescuing crew members from the burning ship and those struggling in the water.

The loss of the Deneb marked a significant setback for the Dutch naval forces in the Riau Archipelago as this attack had effectively closed the ports of Sabang and Belawan to Allied operations.

The loss of safe passage through the Malacca Strait also forced shipping to the United States to take longer routes through the Indian Ocean, further complicating Allied logistics in the region.

Reynolds, an experienced navigator with nearly two decades of exploration in Malaya, Burma, and the Dutch East Indies, was exceptionally suited for the task.

With the assistance of eight Chinese sailors, Reynolds repaired and commandeered an old seized Japanese fishing boat, the Kofuku Maru ("Lucky Ship"), from Singapore Harbor.

Using his extensive knowledge of the region, he successfully transported the Dutch refugees to safety in Rengat, a small port on the Indragiri River in Sumatra.

The fall of Dutch defenses shattered this perception and created a growing sense of self-confidence and national consciousness among the local populace.

Governance in Riau was overseen by a Resident appointed from Syonanto, with the position initially held by G. Yogi, a former elite member of the Kwantung Army.

District areas such as Tanjungpinang, Tanjung Balai Karimun, Dabo Singkep, and Tarempa were headed by To Co, while subdistricts (onderdistricthoofd) were managed by Sonco.

As Subi Island's strategic importance lay in its location facing the South China Sea, making it a target for both Japanese fortification efforts and Allied attacks.