Board Thread:Wikia Discussion/@comment-25683568-20150318062713/@comment-26154973-20150620160846

But the game uses 13号, not the full name (三式一号 or 一号三型,, they are numbered, but not exactly in decimal system), so it should be 13 with whatever word instead of Mark, since Mk. is already used for other purposes in-game. In case of numbered CA guns 号 is No. already.