But I still feel those are still more rules than necessary. Hence, I’d like to propose a simpler ruleset that required very few assumptions and priors, even without rules regarding territory, but still looks like it would naturally evolve to Go as we know it today.
#1. Each side places a stone on the intersection of the board. One after another, and no pass.
#2. When a stone is placed it cannot be moved, a stone has 4 liberties and shares liberties with neighboring stones.
#3. When a group runs out of liberties, they are flipped upside-down and are considered captives of the opponents. but are not removed from the board, and captive stones don’t reduce the liberty of a group.
#4. Play until no spot is left open on the board, and the game ends.
#5. The player with more captives wins the game.
These rules have some very interesting effects.
1st, a game will always consist of exactly the same number of moves as the number of intersections. No more, no less, since no stone is taking out of the board, even the captives.
2nd, suicide is allowed by default (although players wouldn’t have the incentive to do so early on), but sometimes might be forced to, like if it is the last legal move on the board, and have to be played since there is no pass.
3rd, at the end of the game, if every spot is filled, except each side has just one eye space left, then the second to last move for that player is also suicide inside the opponent’s eye, and give one captive, in return the opponent is also forced to suicide give one captive as well. And the game will end in a draw.
4th, there is no ko of any kind existed, and a group will be completely safe once it has captured at least one stone inside. We can call it the “one captured eye area is alive” rule. It is not manually defined but derived from basic rules.
5th, creating separate eyes is crucial even if they haven’t captured any captives yet. It’s not because they make the group alive, but because they are captive traps, where your opponent at the end of the game has less “open area” than you, every move afterward is either filling dame points (space not in safe space, and not surrounded), and then backfilling their own areas that still have liberties left(and yields no points), and finally forced to give captives (to prevent suicide, and giving huge amount captives to the opponents).
6th, A safe “eye space” don’t have to be one intersection, as long as it is not sufficiently large enough for your opponent to create at least one “captive’s trap”, it is like a “safe space”, and can be left open till the end of the game. (and due to this, a seki with both sides has one eye in modern go would simply be alive, in no eye seki the one to play first loses, one side has an eye always win)
7th, when each side is left with only “safe space”, the best course of action will be backfilling your own safe space, instead of put stones in your opponent’s safe space and making it alive by default.
8th, experienced players don’t need to fill every space to be able to tell who wins the game, since it is essentially the same as a settled game in modern go. Fill the dame first, then similar to the area scoring procedure to fill in your own territory. And it can be done with area scoring as well, and there is no difference between these two “methods”.
9th, Players who have good global position sense still have the upper hand, while handicap stones cause a severe penalty. And you would want your groups to connect together as much as possible, and cut off your opponent’s groups, since in the end-game backfilling, your opponent needs more stones to form boundaries, and have to sacrifice more captives in your safe zone to prevent suicide.
10th, Due to trying to connect groups and cut off opponents, fighting would be even crazier since it would be much easier to live in a very small group. And 2nd line stones will be quite favorable since one eye on the side first essentially make it alive till the end game.
I think it is simple enough to be learned quickly, almost no ambiguity, a fixed amount of total moves, and yet interesting enough to be fun. And it shares the basic principle where the one with the larger “area” wins the game like Go, which could easily be converted to other variations of Go, by introducing the recapture area rules.
I wonder what would be the game of this precusor Go would look like if we just follow these 5 rules only?