32nd Army Headquarters Bunker (Shuri Castle Underground)

The 32nd Army Headquarters Bunker is an extensive underground tunnel complex excavated beneath Shuri Castle, the historic seat of the Ryukyu Kingdom, in the Shuri district of Naha, Okinawa. It served as the supreme command post for all Imperial Japanese Army operations during the Battle of Okinawa (April-June 1945), the bloodiest campaign of the Pacific War.

Construction

The 32nd Army was established on March 22, 1944 (its organization began in Fukuoka on March 25) to organize the defense of the Nansei Islands. Construction of an underground headquarters initially began at Tsukayama in the summer of 1944, but after the air raid of October 10, 1944 the site was judged unsuitable because of its weak mudstone roof and its poor view of the battlefield. In December 1944, construction shifted to beneath Shuri Castle, where the limestone bedrock provided superior structural integrity. The tunnels were dug primarily by mobilized labor, including Okinawan civilians, middle school students, and Korean conscript laborers, under grueling conditions. The headquarters, which had moved into the Okinawa Normal School buildings in January 1945, transferred into the bunker on March 23, 1945.

The completed facility consisted of five tunnel branches radiating from a central corridor, spanning approximately 375 meters in straight-line distance and an estimated 1,000 meters in total tunnel length. The deepest sections reached approximately 30 meters below the castle grounds. The tunnels housed command rooms, staff offices, communications centers, cipher rooms, kitchens, medical facilities, and living quarters for approximately 1,000 personnel. On March 24, 1945, Chief of Staff Lieutenant General Isamu Cho affixed a wooden nameplate reading "Amenoiwato Battle Command Post" (天岩戸戦闘司令所) at the entrance.

The Battle of Okinawa

Lieutenant General Mitsuru Ushijima, commander of the 32nd Army, directed the defense of Okinawa from this bunker. His force of approximately 100,000 troops employed a strategy of attrition warfare from fortified positions centered on the Shuri Line, inflicting massive casualties on the attacking American forces of the U.S. Tenth Army. The Japanese defenses held from April 1 through late May 1945, despite relentless naval bombardment—including shelling by the battleship USS Mississippi—and constant air attacks that reduced Shuri Castle above to rubble.

As American forces closed in from multiple directions, Ushijima convened a critical command conference on the night of May 21-22, 1945, during which the fateful decision was made to abandon the Shuri position and withdraw to the Kiyan Peninsula in southern Okinawa. On the night of May 27, under cover of darkness and heavy rain, the 32nd Army headquarters staff evacuated through the tunnels and retreated south to Mabuni (Hill 89). Explosives were detonated to collapse the tunnel entrances and deny the complex to American forces.

Seriously wounded Japanese soldiers who were unable to walk were left behind during the withdrawal, and many died. On May 29, U.S. Marines of the 1st Battalion, 5th Marines occupied the devastated ruins of Shuri Castle above.

Ushijima and Cho established their final command post at Mabuni, where both committed ritual suicide on June 23, 1945, effectively ending organized Japanese resistance on Okinawa.

Current Status

The tunnel complex remains largely sealed and inaccessible to the public. Five tunnel entrances are identifiable, though most are overgrown, damaged, or blocked by locked gates. Sections of the tunnels have suffered ceiling and wall collapses, and large portions remain buried under soil and debris from the 1945 demolition. The Okinawa Prefectural Government has been conducting surveys and promoting preservation efforts, with plans to partially open the 5th tunnel entrance and eventually the 1st tunnel entrance near Shureimon Gate as part of the Shuri Castle reconstruction project.

This site is distinct from the Former Japanese Navy Underground Headquarters (旧海軍司令部壕) in Tomigusuku, which was the separate naval command post under Rear Admiral Minoru Ota, located approximately 5 kilometers to the southwest.