rod03801: Oh, sure it can done using notes, or post-its, or using a legal pad.

But that 1) requires to have a notes entry field, which I rather keep as tiny as possible (or rather, not show at all), as it takes up valuable screen estate on the games I don't need to keep notes; 2) requires one to consult the notes each and every time; 3) make the mental adjustment between algebraic notation and the game field; 4) have to do work which is better done by computes (and didn't Fencer write once on his blog he doesn't like to do work that could easily be done by computers?).

My request isn't that it's impossible to keep track of guessed squares. But that game play would be so much more enjoyable if it was shown on the field. (Considering that there's little to gain to guess again on an already guessed field, Fencer may even go the extra step and make an already guessed square unclickable).