8. ...jxB
so I take it after pawn moves, a joker can capture diagonally, but not en passant since that isn’t a normal capture?
Good question. I have sent a mail about this to the inventor of the Joker, Henk van Haeringen.
But I tend to say, yes the Joker can take en passant. En passant is a weird move, but still part of the 'normal' movement abilities of the pawn. Where promotion certainly isn't. So this is one way to look at it. But it would also be arguable to count en passant as a special function.
With the Joker, these things need to be defined on case by case basis.
I prefer to wait for the inventor's answer and let that be definitive. I have trust that we won't run into the situation before I get the reply.
8. ...jxB
so I take it after pawn moves, a joker can capture diagonally, but not en passant since that isn’t a normal capture?