With regards to Go, I would say there are certainly more than five rules. The object of the game is part of the rules. That implies one must understand how to recognize the end of the game and how to calculate the scores. One must also understand the concept of two eyes needed to make a group safe. I would call that part of the rules, not implied from simpler rules, because with out the two eyes rule, the rules are most confusing and potentially ambiguous. There are also some esoteric and rarely encountered rules which beginners need not concern themselves with, such as agreeing on komi for a scoring offset, mutual stalemate positions, and dealing with three ko situations at once. Overall, the rules are relatively simple nevertheless, so your main point was valid.But the rules to Go are not nearly as simple as an abstract game can get. I recommend you check out the board game Hex. Look on Wikipedia or BoardGameGeek for Hex board game. I strongly urge you to use the pie rule, which makes the game much more balanced and thereby deep. Hex has tons of emergent complexity and variety in strategical choices. By my count, I would say Hex has five rules:1. The board, usually an 11x11 rhombus of hexagons, is empty at the start.2. Two players, usually black versus white, take turns placing one stone at a time on any empty cell, with black moving first.3. The rows around the edges are called border rows, with black border rows clockwise from the acute corners, and the four corner cells are each part of both adjacent border rows.4. Pie rule: after black places the first stone, the other player has the option, at that moment only, to swap sides. If sides are swapped, the player who moved first as black is now white, and places the next stone. Sides may be swapped at most once per game. If the second player chooses not to swap after black's first move, then sides may not be swapped at all that game.5. The object is to connect your border rows with a continuous path of your stones.An emergent fact from the previous rules is that draws are impossible, that one player will always win. But I would not call that a rule. IMO Hex has the simplest rule set of any interesting game.