Would a Japanese battleship with four quadruple 14-inch turrets be better than Yamato at fighting multiple capital ships?
Short answerNot necessarily as a ship, but adopting 14-inch guns could give Japan major leverage by locking rivals into the same treaty caliber.
NotesFour quadruple 14-inch turrets would deliver a formidable sixteen-gun broadside. The smaller caliber would not by itself solve Japan's inability to build enough battleships for the strategy assigned to them. Its larger effect might be diplomatic: Japan could accept the 1936 14-inch treaty ceiling. That agreement would obstruct American plans centered on 16-inch guns even if the alternative Japanese ship remained strategically overambitious.