One step at a time

I changed how Pawn-sacrifice is initiated, by limiting Serpent to its neighboring fields. As a consequence, Pyramid is now activated with only one momentum, so sacrificing Pawn is also limited to only one step. While change itself is rather small, and it applies to only one special movement, there are a few design choices worth pointing out.

The issue with Pawn-sacrifice was that one could lose quite a few Pawns, and in turn have promotion opportunities severely limited or completely gone, all in only one move. Also, in its original form, Serpent could initiate Pawn-sacrifice by activating Pyramid from across a chessboard. It was also possible for a Serpent to slither around pieces and still find a way to its own Pyramid. Similarly, Pyramid activated with a lot of momentum could sacrifice Pawn at the other side of a chessboard.

In my defense, when Pawn-sacrifice was originally conceived, Serpent's movement was much more limited, up to 9 fields in the largest variant, 8 otherwise. In the mean time, I extended Serpent's reach, but failed to notice its impact on Pawn-sacrifice. By limiting Serpent to its neighboring fields, one now has at least some warning signs (Serpent, Pyramid and Pawn placed close to each other) what is about to happen, and an opportunity to counteract that kind of a move.

I'm also updating the book, Pawn-sacrifice is the only meaningful change. The book was compiled on July 29, 2025, version is 20250729.034138, and can be found in other usual places.