Hello fellow little golems, I've been working on a little text about Sither (“guide” would be too much). You can find it here:

Link to pdf file (1+6 pages)

Any feedback is highly welcome! What I am going for, and what kind of help I would love to get, is explained on the first page. Don't worry, you would already do me a huge favour by reading the words and looking at the diagrams, and telling me whether it's been worth your time.

Thanks, David

This is really cool and useful ! thanks !

Excellent work, David!

Very nice! I like this idea in general; the rules alone don't give you a sense of what the strategy will look like.

A comment on the explanation in “Consequences of diagonal prohibition”: you say things like the pieces “cannot move,” but it appears that they can so long as the subsequent placement move corrects the diagonal issue. Clearly that's less good than just being able to move without having to use the placement, so I understand the value of recognizing these patterns, but I was a little confused at first.

I did also find a few typos:

“As in all connection games, the presence of just a single opposing stone in the way of a prospective connection is desirable already prolongs that connection.” Seems like the end of this sentence shouldn't be here?

“…a corner player is much worse than…” I believe you mean “a corner play”

“…and is allowe to move…”

Many thanks for the kind feedback! I've uploaded a newer version. It has a rule change: Luis Bolanos Mures pointed out that stalemate has been declared to be  a forced pass (not a loss). I think that's reasonable, especially since no two-sided stalemates can occur (that's proved in an interesting formal article on Slither by Edouard Bonnet, LG Slither champion Florian Jamain and Abdallah Saffine). In practice, this won't matter too much, but Slither is rule-wise troubled enough, so I'm happy to stick with the new-to-me official rule.

Moreover, there is one additional problem, by Ralf Gering.

I still think that the swap rule does not work well, but I changed my stance on what to do about it: I believe that the first player should have a handicap in the form of not being able to move for N turns. The number N has to depend on the board size, and I have no clue what a good starting value could be on the 9x9 board. Perhaps N=6? This is a bit like komi in Go, which has been massively increased since its invention in the 1920s.

Feedback is still, and always, welcome! I've got one more idea of a Slither concept that I might be able to explain, but apart from that, I have to rely on your input :)

Great job, thanks!

I've never realized before that the grids are there to claim empty rows and columns. My intuition about it is different; I'm going to try to explain it. There's no right and wrong way to think about it; use whatever helps you.

Consider a position in which somebody has won. If we place a cross pentomino centered onto any position on the winning path, it will have at least 3 stones of the winning color - assuming that arms of the cross that fall off the board are considered black (for vertical arms) or white (for horizontal arms). It's therefore possible to think of Slither as some sort of ConHex, with stones being votes necessary to win crosses, and a path of interlocking crosses with 3 votes wins the game. But for a ConHex player it's very natural to spread the votes thin. This is where the knight's move grid comes in: it places 1 vote onto every cross on the board.

It changed since the last time I read it!

A really great job.

Some comments.

1/ Maybe you could precise “after a 'complete' turn” the following…” in the introduction, or something. I mean when you move a piece, it is allowed to reach a diagonal position if it is corrected by the stone you place in the same turn. This is not obvious I guess.

2/ When you talk about strategies, maybe point out two different things. Some are really related to the dynamic of Slither or the fact that a move is separated in 2 parts (possibility to move and to put a piece at 2 different places on the board), some others are the same in many connection games (Hex/TwixT…): 'building perpendicular wall', even many games: 'local dominance' for instance.

3/ Before “problems”: for each single game you present in the book, you should at least give one example of problem and propose/explain the solution with multiple diagrams if needed.

4/ Do we have some statistics on the winners? I mean between first and second player, second player cause of swap is really winning more? What is the %?

5/ I don't think it is really important to be 2nd to swap, the advantage is not that much important when the size of the board is not too small. My way: Remove swap rule, just start the game with a black piece in a corner, white to move.

Time for another update: the text now is at 7 pages (which is unfortunate, because for a silly reason, I need even numbers), and it has 9 problems. As before, the problems could be better, but it's a start. I've added a section on edge ladders which is the last heuristic I could come up with (I'm sure there are more).

Many thanks for the great feedback! I didn't incorporate yours yet, alihv, but I have it in my notes on Slither. Thanks for making that connection, too – I'd never have thought of Slither like this.