I think seki is just one complication out of many that arise from the potential complexities of determining life and death under Japanese rules.
Under Chinese and other area scoring rules, it’s possible to further simplify the endgame position by playing on to capture strategically dead stones (indeed, this is method to resolve disputes and requires no advanced reading skills on the part of the arbiter). This is possible, since these additional plays won’t change the final score.
On the other hand, with Japanese rules, play is often strategically forced to end with some stones left uncaptured, and requires the arbiter to work through all of the complexities of life and death with careful reading (possibly assisted by the players). Further, there are some nuances and weird situations that only seem to arise in the Japanese rules:
- Determining life and death in the confirmation phase (after both players have passed) considers hypothetical perfect play with a different ko rule than is normally used during the rest of the game. It’s possible for stones to not be killable or saveable during normal play, but only die during the confirmation phase.
- It’s possible for both players to lose if they make the mistake of leaving a decisive, unsettled position on the board.
- It’s possible to have stones that are declared dead during confirmation but not removed for counting the score, in the case of anti-seki.
- The case of Moonshine Life seems to lead to a possible endless loop during the confirmation phase. However, the Japanese rules clarify and provide a special ruling for this particular pattern in the official commentary.
While these issues are quite rare, their possible existence means that any software needs to be ready to handle some difficult edge cases, makes developing a solid algorithmic approach to life and death under Japanese rules quite challenging.