The , or was one of the armaments expansion plan of the Imperial Japanese Navy (IJN).
Background In August 1941, the IJN started building warships for war. It extended to 293 vessels, 300,000 tons.
Table of vessels Category Class Vessel number(s) Completed Converted Cancelled Heavy cruiser Ibuki #300 - 301 #300 was converted to aircraft carrier #301 Aircraft carrier Unryū #302 Unryū (#302) Seaplane tender Akitsushima #303 #303 Fleet oiler Kazahaya #304 - 307 Kazahaya (#304) #306 was converted to the Hayasui class #305, 307 Hayasui Hayasui (#306) Escort ship Type-A Etorofu #310 - 339 Etorofu (#310), Matsuwa (#311), Sado (#312), Oki (#313), Mutsure (#314), Iki (#315), Tsushima (#316), Wakamiya (#317), Hirado (#318), Fukae (#319), Amakusa (#321), Manju (#323), Kanju (#325), Kasado (#330) #320, #322, #324, #326 - 329 and #331 - 339 were converted to the Mikura class Escort ship Type-B Mikura Mikura (#320), Miyake (#322), Awaji (#324), Nōmi (#326), Kurahashi (#327), Chiburi (#329), Yashiro (#331), Kusagaki (#334) #328, #333 and #339 were converted to the Hiburi class#332 and #335 - 338 were converted to the Ukuru class Hiburi Hiburi (#328), Daitō (#333), Shōnan (#339) Ukuru Ukuru (#332), Okinawa (#335), Amami (#336), Aguni (#337), Shinnan (#338) Destroyer Type-A Yūgumo #340 - 355 Hayanami (#340), Hamanami (#341), Okinami (#342), Kishinami (#343), Asashimo (#344), Hayashimo (#345), Akishimo (#346), Kiyoshimo (#347) #348 - 355 Destroyer Type-B Akizuki #360 - 369 Shimotsuki (#360), Fuyutsuki (#361), Harutsuki (#362), Yoizuki (#363), Natsuzuki (#364), Hanazuki (#366) #367 - 369 Cruiser submarine Type-B I-40 #370 - 375 I-40 (#370) to I-45 (#375) Cruiser submarine Type-C I-16 #376 - 378 I-46 (#376) to I-48 (#378) S49B #379 - 381 #379 - 381Medium-sized submarine Ro-35 #385 - 396 Ro-44 (#385) to Ro-50 (#391), (#396) #392 - 395 Ro-100 #400 - 408 Ro-109 (#400) to Ro-117 (#408), Minesweeper No.19 #410 - 437 No.25 (#410) to No.30 (#415), No.33 (#418), No.34 (#419), No.38 (#423), No.39 (#424), No.41 (#426) #416 - 417, #420 - 422, #425, #427 - 437 Subchaser No.13 #440 - 459 No.40 (#440) to No.58 (#458) #459 Minelayer Ajiro #460 - 473 Ajiro (#460) #461 - 473 Auxiliary minesweeper Aux. No.1 #480 - 495 Aux. No.7 (#480) to Aux. No.22 (#495) Auxiliary subchaser Aux. No.1 #500 - 599 Aux. No.1 (#500) to Aux. No.100 (#599) Patrol torpedo boat No.10 #600 No.10 (#600) No.11 #601 - 617 No.11 (#601) to No.16 (#606) #607 - 617
See also 1st Naval Armaments Supplement Programme (Maru 1 Keikaku, 1931) 2nd Naval Armaments Supplement Programme (Maru 2 Keikaku, 1934) 3rd Naval Armaments Supplement Programme (Maru 3 Keikaku, 1937) 4th Naval Armaments Supplement Programme (Maru 4 Keikaku, 1939) Temporal Naval Armaments Supplement Programme (Maru Rin Keikaku, 1940) Additional Naval Armaments Supplement Programme (Maru Tui Keikaku, 1941) 5th Naval Armaments Supplement Programme (Maru 5 Keikaku, 1941) 6th Naval Armaments Supplement Programme (Maru 6 Keikaku, 1942) Modified 5th Naval Armaments Supplement Programme (Kai-Maru 5 Keikaku, 1942) Wartime Naval Armaments Supplement Programme (Maru Sen Keikaku, 1944)
References Rekishi Gunzō series, Gakken (Japan) The Maru Special series, Ushio Shobō Daiji Katagiri, Ship Name Chronicles of the Imperial Japanese Navy Combined Fleet, Kōjinsha (Japan), June 1988, 大日本帝国海軍艦艇一覧 (ja)