As some background, in the pre-engine era time-controls were often slower and chess players could [adjourn][1] their games, taking a break till the next day and resuming from the same position.

In all turn-based boardgames where this is or was an option, as far as I can see (chess, Go, Shogi, ...), adjournment was accompanied by 'move-sealing': one player writes down the move they will make, the other player does not see it, and the next day play begins with this move.

This was obviously a measure to avoid the inequity of discontinuing the game in a position where one player knows the exact gamestate while preparing his move. (For example, if I play my move openly rather than sealing it, and the game then adjourns, my opponent has an advantage because he can prepare a response to that exact move.) However, it is not obvious to me that this avoids inequity: there is a clear advantage for the sealing player, as they will know the starting gamestate the next day and the opponent will not.

What is the justification for this second advantage being less than the first?


  [1]: https://en.wikipedia.org/wiki/Adjournment_(games)