'Shinryu' was a Japanese unrealised plan to attack the US naval forces off Guadalcanal in the south-eastern part of the Solomon islands group using midget submarines (25 September 1942).

On this date, only days two weeks after the Japanese land forces on the island had suffered a sanguinary defeat in the Battle of Bloody Ridge, the seaplane carrier Chiyoda departed Kure in the Japanese home islands without escort for Truk atoll in the Caroline islands group carrying six 'Type A' midget submarines, but the operation was then cancelled.