San Shiki (anti-aircraft shell)

San-shiki-dan (三式弾, "Type 3 shell") was a World War II-era combined shrapnel and incendiary anti-aircraft round used by the Imperial Japanese Navy.

On 13 October 1942, in order to help protect the transit of an important supply convoy to Guadalcanal that consisted of six slower cargo ships, the Japanese Combined Fleet commander Isoroku Yamamoto sent a naval force from Truk—commanded by Vice-Admiral Takeo Kurita—to bombard Henderson Field.

Kurita's force—consisting of the battleships Kongō and Haruna, escorted by one light cruiser and nine destroyers—approached Guadalcanal unopposed and opened fire on Henderson Field at 01:33 on 14 October.

Even though the 3 Shiki tsûjôdan shells comprised 40% of the total main ammunition load of the Yamato-class battleships by 1944, they were rarely used in combat against enemy aircraft.

[6] Yamato fired these shells in two separate instances during Operation Ten-Go, first against PBM Mariner flying boats shadowing her, and later against the attacking aircraft of Task Force 58.