According to ONI 41-42 Japanese Naval Vessels (dated Nov 9 1942)
Yamato and Musashi are listed as BB-11 and 12 respectively, of unknown or unique class.
Tosa and Owari are listed as 13 and 14, and as "reported building"
There are no silhouettes given in the section for the BBs under "N _ _ Notes" pretty sad to see racial slurs like that used in official documents back then, but maybe I shouldn't be suprised...
Under Japanese naval ordanance,
Tosa, Owari, Musashi, Yamato, they're incicated to have 9 main guns, a nominal bore of 16", caliber is left blank, actual bore is listed as "16" ?"
there is lots of information there for other ships - range at certain angles, penetration, muzzle velocity, but the yamato appears to be unknown at this time.
Chern
*edited for content* sorry folks

don't mean to offend!