This is what Mervyn has.
It is a Dumpy Level used for getting things level (as you might expect) I am very suspicious about it being a WWII Japanese military relic for a number of reasons.
It's the wrong colour to be a piece of Military kit. Yes,.. I know that the Japs probably borrowed civvy materiel too, but I doubt that they would not have given it the obligatory coat of military paint.
It looks too modern to be from that era, but looks more like similar levels from the 1950s and 60s.
Has anyone any experience here?