Judging by the barrel and chassis, the Yakumo tank is a Merkava, type 3 or 4, but the text states it has a 104mm cannon. The type 1 and 2 had a 105, but the 3 and 4 use the 120. Also, the driver's position is in the hull.
Maybe a forgotten prototype? I mean, if it weren't one then it could'ven't drifted to gensokyo
