late 1943, because the IJN was planning to build the . Boats in class Characteristics Footnotes Bibliography, History of Pacific War Vol.17 I-Gō Submarines, Gakken (Japan), January 1998, Rekishi Gunzō, History of Pacific War Vol.35 Kō-hyōteki and Kōryū, Gakken (Japan), April 2002, Rekishi Gunzō, History of Pacific War Vol.36 Kairyū and Kaiten, Gakken (Japan), May 2002, Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005, Model Art Extra No.537, Drawings of Imperial Japanese Naval Vessels Part-3, Model Art Co. Ltd. (Japan), May 1999, Book code 08734-5The Maru Special, Japanese Naval Vessels No.31 Japanese Submarines I'', Ushio Shobō (Japan), September 1979, Book code 68343-31 See also Cruiser submarine Submarine classes Submarines of the Imperial Japanese Navy