'Aq' was the Japanese seizure of Attu island in the Aleutian islands group as part of the larger-scale 'Al' undertaking (7 June 1942).
Attu island lies near the western end of the Aleutian islands chain, some 740 miles (1190 km) to the west of Dutch Harbor on Unalaska island and just 650 miles (1045 km) from Paramushiro island in the Japanese-controlled Kurile islands group. It is about 38 miles (61 km) long and 14 miles (23 km) wide and, like most of the Aleutian islands, is mountainous and barren, with a maximum elevation of 3,084 ft (940 m) toward its western end. The few beaches are narrow and steep and there are numerous offshore rocks and strong currents. There are, however, some small protected anchorages, at Holtz Bay, Chichagof Harbor, and Massacre Bay. As the time of the Japanese landing, the only inhabitants were 39 Aleuts and an elderly white couple serving as schoolteachers at the village of Chicagof. There was also a small party of US weather observers.
Under the supervision of Lieutenant General Kisaburo Hamamoto’s Northern District Army, the Sapporo-based formation whose primary responsibility was the defence of northern Japan (Hokkaido island as well as smaller islands including Karafuto and Chishima), the occupation was undertaken by a 1,200-man force of the 301st Independent Battalion under the local control of the Attu Occupation Force, which landed in Massacre Bay and quickly took the village of Chichagof before interning the small local population.
Late in September 1942 the Japanese transferred their garrison on Attu island to Kiska island. Despite the fact that Attu was then left essentially unoccupied, the US forces made no attempt to occupy the island during this time. On 29 October 1942, the Japanese re-established a base on Attu island at Holtz Bay under the command of Lieutenant Colonel Hiroshi Yanekawa. The garrison at first numbered only about 500 men, but the subsequent arrival of reinforcements increased the total to about 2,300 men by 10 March 1943. No additional reinforcements arrived after that time.
The Japanese garrison was provided by men of the 301st Independent Battalion and 303rd Independent Battalion and the North Chishima Coast Defence Infantry Unit, 1,570 of these men being delivered by ship and submarine between November 1942 and April 1943, and these were defeated in the US 'Landcrab' operation to retake the island.