Most possible movement by the losing side in a zugzwang position

Usually, in a zugzwang, the idea is to limit the number of moves that the opponent can make so that they will have to make a bad move. But what if we decided to give them lots of freedom, given that no matter what they do, they lose?

Thus an idea came to my mind for a construction task: What is the highest possible number of moves by the losing side in a zugzwang position?

Without prompted pieces, and counting different promotions as different pieces, I found a total of 73 in the following position.

``````[FEN "6K1/PB2q3/2p1p1k1/1NNPB3/6P1/1p4p1/1QPPPP1P/R6R w KQkq - 0 1"]
``````

Yes, this is actually a zugzwang position for White. No matter what defense they employ, there are simply too many mating threats by the Black queen to handle. It's a mate in three at most according to Stockfish.

Is better possible for without promoted pieces? What about with promoted pieces?

I don't mind if you give an already known position-I highly encourage it in fact!

And have fun and good luck if you are making a new position on your own!

• Is this really a zugzwang position? What I always learned about them is that if the winning side is to move, they either can't win at all or need to do so with a manoeuvre giving the same position with the other side to move. Here, black to move mates in 2 starting with Qf7+. – Glorfindel Jun 24 at 6:56
• If black is to move, aren't ...Qe8 and ...Qd8 mate? Or did I miss anything? – Rosie F Jun 24 at 8:03
• This is not zugzwang -- it is simply winning for Black, whoever has the move. – TonyK Jun 24 at 13:28
• The reason why this isn't zugzwang is that white still loses if they were to "pass". Zugzwang is the tactical motif where a side would be fine if they could "pass" their turn without making a move, but is disadvantaged by any move they make. While there are many positions where a side loses whatever move they make, far from all of them are zugzwangs. – Scounged Jun 24 at 14:09
• "Well I also learned is that a zugzwang position is one in which all possible moves are losing," You either misunderstood the explanation, or the explanation was poorly worded. "losing move" is ambiguous as to whether it means it puts the player in a losing position, or puts the player in a worse position. Zugzwang is a position in which every move is "losing" only in the second meaning. If every move puts the player in a losing position, then they are already in a losing position, so that's not zugzwang. It's just a losing position. en.wikipedia.org/wiki/Zugzwang – Acccumulation Jun 24 at 15:51

The following are full-point zugzwangs, so both sides are losing if either moved!

``````[Title "Noam Elkies. EG 128, Apr 1998, p.53, 10967 (v)"]
[StartFlipped "0"]
[fen "8/8/k7/8/K7/RNbn4/B7/1R6 w - - 0 1"]

1. Rc1 Nb2#
``````

White: 8 with wRb1, 6 with N = 14. Black: 11 with B, 8 with N, 3 with K = 22. Total-36.

``````[Title "Noam Elkies. EG 128, Apr 1998, p.53, 10967 (text, v)"]
[StartFlipped "0"]
[fen "8/8/8/k1n5/8/K7/RRb5/QBb1n3 w - - 0 1"]

1. Bxc2 Nxc2#
``````

White: 1 with B = 1. Black: 9 with Bc2, 6 with Bc1, 8 with Nc5, 3 with Ne1, 1 with K = 27. Total-28.

If you allow promoted pieces in the diagram: The following is a half-point zugzwang.

``````[Title "half-point zugzwang: WTM draws. BTM loses in 14"]
[StartFlipped "0"]
[fen "3q4/8/4q3/2Q5/k7/8/8/2K4Q b - - 0 1"]

1... Qg5+ 2. Qxg5! Qc4+ 3. Kd2
``````

It is a draw if it is white to move. Meanwhile, if it is Black to move, they lose in 14 moves. Black has 25 moves with Qe6, 21 moves with Qd8, and 1 with Ka4, for a grand total of 47.