I've invented, or maybe just reinvented, a new kind of chess problem that is (I hope) immune to being solved by chess engines. It involves one or both sides having two kings!
Other than that, all the other rules of the game stay the same, so these problems still feel like normal chess problems. They just involve these two extra rules dealing with the new situations that can arise when you have two kings:
- The only way to checkmate a player is to checkmate both kings simultaneously.
- If one or both of a player's kings are put in check, and it's only possible to get one of them out of check, the game is a draw. (Basically, the player is not checkmated, but has no legal moves, which can be seen as a more general formulation of the existing stalemate rule.)
And that's it! But rule #2 is tricky, and so might be worth some clarification:
- If both kings are in check and there's no move that gets either king out of check, then that is simply checkmate, according to rule #1 above.
- If the opposing player can get both kings out of check (for example, by capturing the piece that's checking both kings) then the game simply goes on.
- Conventional stalemates, in which neither king is in check but there are still no legal moves, still count as draws.
Here's an example of a Twin Monarchs checkmate:
Both black kings are in check and neither of them can escape.
Here's an example of a Twin Monarchs stalemate:
Both black kings are in check, and while either of them could easily escape it, both can't at the same time.
Finally, here's another way to stalemate twin monarchs:
Only one king is in check, but it can't get out of check without exposing its twin to a check.
As you work on my problems, I'd love to get your feedback on the following questions:
- Did I make any mistakes? Do any of these problems have extra, unintended solutions (a "cook") for example? I had them checked by John Bartholomew, a strong International Master and popular Twitch streamer and YouTube content creator, but he is, of course, only human, and he couldn't double-check his checking by running these problems through an engine.
- Is this a kind of problem that already exists? John said he's seen some double-checkmate problems before, in the book The Soviet Chess Primer, but at the time the original Russian edition was written, there were no chess engines, and so the problems would have just been fun oddities. I can't find anything like them on the Internet, though, in this age when problems like this, that can't be solved by engines — at least until someone modifies Stockfish with my new rules! — could be a big thing.
- Or are these problems solvable by a chess engine? I'm just assuming that having two kings per side will make these problems impossible for any chess engine to swallow, much less digest, but who knows? Try it on yours and let me know if it can stomach it.
- How good can problems of this type get? I'm just a casual player with zero experience composing problems, so my compositions below are not that hard and have all kinds of aesthetic flaws, but I wonder what a real composer could do in this domain. I think my Twin Monarchs stalemate rule — which is maybe the real advance here — offers lots of fertile ground for creative problems, but will the need to mate both kings at once limit the possibilities for Twin Monarchs checkmate problems?
And here we go:
White to play and mate in two
White to play and draw
You can find the solutions here.