Comment by ramly

I was not! Just checked it out, great to see other chess variants out there. This looks like a simple but fun ‘clear the board’ puzzle. Here are the main differences with echo chess as far as I can tell:

1) No echoing mechanism. In echo chess, if you capture a pawn, you become that pawn. That means the maze effectively changes at every capture. The post linked above has a thorough analysis (and visual examples) of the strategic implications and limitations of this simple twist, so I highly recommend checking it out.

2)Forced to capture at every move. Solitaire chess seems to require a capture at every move. While that may appear to be a more difficult setting at first sight, it can actually lead to a much lower search space complexity by heavily restraining the degrees of freedom. In small enough puzzle boards, backtracking can become trivial.

3) No white pieces, so no squads, and no sacrifices. In echo chess, it’s white against the world. In future levels (starting 9), you get a squad of white pieces to use. This quickly becomes a double-edged sword: your ally is also a blocker on your quest. Higher levels even require you to sacrifice an ally piece in your squad to solve the maze. This adds a whole new level of strategy and complexity to the game.

4) Endless mode with ML. The ‘endless’ mode of echo chess continuously serves procedurally generated chess mazes in real time that are guaranteed to be solvable (with 99%+ accuracy) every time you solve a prior one. You carry over your white piece and ending square as a starting position for the next level. This adds a tremendous amount of replayability, variability, and continuity for the game. It essentially becomes a strategic Tetris variant.

There are lots of other differences and nuances but I really think the post linked above does a better job analyzing them. If you’re an experienced solitaire chess player, I’d love to hear your thoughts on echo chess once you try it out!

Thanks for sharing this cool variant too. I’ll make sure to give it a try :)