[zelphirkalt]

While knights move similarly, involving other rules about their movement, in Shogi and Xiangqi, I also played a chess version, which I think was Korean, (now looked it up: Ah, it is called "Janggi") with a program once. There the knights moved differently.

As a chess and chess variants player, who thinks about geometrical features of the game and pieces, especially the knight, one will have thought about most of the things described in that post, or they will seem immediately clear: "Yes ofc, that is because ...". However, if one is not a mathematician or looks at these things in detail, one might not have used the mathematical terminology or have known how to describe some criteria for a generalized knight reaching squares.

I find it also interesting, for how many chess players chess and software development in ones spare time go together. Chess can serve as a source for many interesting projects.

[zzo38computer]

In shogi, the 桂馬 moves like the knight but only the two forward most moves; it can still jump. However, in shogi it can promote (most pieces in shogi can promote).

In xiangqi, the 馬 moves like the knight, in any direction, but it can be blocked (it is considered to go one orthogonal and then one diagonally outward); it is possible that one 馬s threatens the other, but not other way around because the opponent's one is blocked. (The rule that the kings are not allowed to look at each other can also have this non-mutual attacking effect, but 馬 does it even independently of that rule, and of the river.)