I do not think I have expressed myself well about the joker. The K and J do manage to force the enemy king to the corner, but then it is not doing the obvious checkmating move.
Ok, I have done some testing and we were looking in the wrong place. The reason it does not do the obvious checkmating move is because that move is not checkmate, it is stalemate. Until that point, the computer thinks it is ahead by one Joker. It doesn't want to trap the King in the corner with the Joker because that ends the game in a draw.
Per an earlier discussion, the Joker only has movement capabilities when its side is on the move. When the other side is on the move, the Joker has no movements at all. So the King in the corner cannot move, because then the Joker would be checking it. But the King is not actually in check before it moves. It has no legal move, so it is a stalemate. I had not considered this situation before. But, under the current rules, King+Joker vs. King is a draw.
Ok, I have done some testing and we were looking in the wrong place. The reason it does not do the obvious checkmating move is because that move is not checkmate, it is stalemate. Until that point, the computer thinks it is ahead by one Joker. It doesn't want to trap the King in the corner with the Joker because that ends the game in a draw.
Per an earlier discussion, the Joker only has movement capabilities when its side is on the move. When the other side is on the move, the Joker has no movements at all. So the King in the corner cannot move, because then the Joker would be checking it. But the King is not actually in check before it moves. It has no legal move, so it is a stalemate. I had not considered this situation before. But, under the current rules, King+Joker vs. King is a draw.