Unknown Off-Pieces Shogi

Rules

This game is mainly the same as shogi, except as detailed below. It is described as if it is a correspondence game, with a moderator for only cases mentioned below.

When a piece is placed off-board onto the board, the kind of piece being placed isn't sent to the opponent (the position is still sent, though). Any other move is still sent: The source and destination cell, and whether or not it is promoting.

The moderator is invoked in case a player tries to place a piece onto the board which is a æ­©å…µ or that he doesn't know for sure isn't a æ­©å…µ. He must try placing it, and then the moderator will tell him if it is valid or not; if it is he must play that move, but if not then it is possible to try another one. Opponent is not told that he tried an invalid move at first.

The other case of the moderator being invoked is trying to move a piece that you don't know what it is. Same as above, you have to try to make such a move, and then they tell you that it is invalid, and you can try any other move. Opponent is not told that he tried an invalid move at first, just like the above. For example if you try to move a 金将 two spaces forward even though you don't know what it is, then you will learn that it is not a 香車 or 飛車 (the only two kind of pieces capable of such a move). This rule even applies if trying to promote a 金将, or trying to move a piece without promoting even though it is forced to promote in such a position.

Notes

Notice that it is also possible when you captured an opponent's piece, you won't necessarily know what kind of pieces it is. Also, you might not know if you are in check. But, it is always known which pieces are promoted.

The possibilities of attempting dropping a æ­©å…µ where it is not allowed includes:

• If you have other unknown pieces in the same column
• If you don't know some of opponent's pieces, whether they can capture your dropped piece
• If you don't know some of your own pieces, whether it is threatening some spaces near opponent's king

One variant might be, on your turn you are told one vacant square (selected at random) which is not allowed to drop anything there unless it is check. Opponent is not told what square that is.

One more variant can be that opponent is told in case an invalid move is tried (but not what invalid move is tried).