Comment by microtherion

Oh, this led me down a rabbit hole…

I was maintainer of the Chess app from the early 2000s to about 2015. We first noticed in 2004 that level 1 (which was then "Computer thinks for 1 second per move) was getting stronger with each hardware generation (and in fact stronger than myself).

So we introduced 3 new levels, with the Computer thinking 1, 2, or 3 moves ahead. This solved the problem of the engine getting stronger (though the jump from "3 moves ahead" to "1 second" got worse and worse).

A few years after I had handed off the project, somebody decided to meddle with the level setting code (I was not privy to that decision). The time based levels were entirely replaced with depth based levels (which eliminates the strength inflation problem, but unfortunately was not accompanied by UI changes). But for some reason, parsing of the depth setting was broken as well, so the engine now always plays at depth 40 (stronger than ever).

This should be an easy fix, if Apple gets around to make it (Chess was always a side project for the maintainers). I filed feedback report 21609379.

It seems that somebody else had already discovered this and fixed it in a fork of the open source project: https://github.com/aglee/Chess/commit/dfb16b3f32e5a6633d2119...