How can a chess game with clock take 5 hours?

In the 4th episode Beth plays against a Russian boy, at some point he says "the game is going on for 5 hours, you should seal your move".

How can a game with a clock take 5 hours? In one of the earlier games the rules was 120 minutes with a max of 60 moves (I think). So assuming the same rules apply for this match, the longest a game can take is 4 hours?

This might be a better fit for Chess Stack Exchange, but the answer could depend on time, location or type of tournament.

The 120/40 clock referred to for the tournament means that the player has to complete the first 40 moves in 120 minutes or they lose automatically.

What is not explicitly stated in the movie is that there are time limits for the next sections of the game. 60 minutes for the next 20 moves is not uncommon -- so a five hour game is well within the rules.

That and more fun chess facts can be found at Chess Stack Exchange, which is where this question probably belongs.

• The 120 minutes for the first 40 moves is for each player, so 40 moves by both sides can take 4 hours. Nov 10, 2020 at 20:07
• This gives an indication of their relative skill levels: her opponent was able to survive 40 moves, which most of her opponents were not. Nov 11, 2020 at 4:21
• @Acccumulation that's about the worst indication of skill level I could think of in chess. Better opponents facing each other will typically have fewer moves before a winner is decided. While a worse opponent might wish to play "to the finish". Nov 13, 2020 at 18:07
• @paul23 I said relative skill levels. The overall skill difference among participants in a tournament is zero, so given that you're talking about the skill level of opponents, plural, you must be talking about absolute skill level, not relative. Furthermore, I am talking about the show indicating relative skill level. Obviously there are better ways in general of evaluating relative skill level, but having a game go on a long time is one of the best ways that a fictional show aimed at a mass audience can show it. Nov 13, 2020 at 18:46
• @Acccumulation showing such a gross misunderstanding is like a show arrogantly showing "dutch" people by throwing extra cheese in the picture: it's offensive for chess players. I'm not saying they aren't doing it for this purpose, I'm stating it's blatantly ignorant and borderline offensive. Nov 13, 2020 at 19:59

I'll admit that I haven't seen the series, but let me just add that 'sealing a move' was common practice when playing with adjournments. That practice has disappeared, over-the-board games are now always finished the same day, but it used to be possible for games to be adjourned if they weren't decided after 40 or 60 moves. Wikipedia lists two common time controls, the first one which matches the scene:

• 2​½ hours per player for the first forty moves, followed by adjournment (a five-hour session)
• Two hours per player for the first forty moves, followed by one hour for the next twenty moves, followed by adjournment (a six-hour session)

Basically, it worked as follows: a player may choose to 'pause' the game by writing down their move, put it in an envelope, seal it and give it to the arbiter. Both players could take the time to analyze the game in great detail (with their second or their coach). The game would then be resumed the next day, or perhaps even later in the tournament, on what was scheduled to be a rest day.

The main benefit of this system would be that the players weren't exhausted from the first hours of the game, so the quality of play would likely increase. The main drawbacks: tournament schedules could become tight, and it was disappointing for the public if you didn't know who won. Imagine a soccer game in a knock-out tournament which (even after extra time) is still equal, and the players decide that they will come back tomorrow to finish it off...

• It might be worthwhile to mention that the reason adjournments are no longer done is because everyone's computer can simply be used to analyze the positions for them. In a theoretical modern adjournment, the result of the position would not be from the players' minds, but from their silicon representatives'. Nov 10, 2020 at 23:58
• There are some slight inaccuracies, such as that her opponent initiated the adjournment, but she was the one who sealed her move. Nov 11, 2020 at 4:03
• A note on your soccer comparison: "In association football, replays were often used to decide the winner in a knock-out tournament when the previous match ended in a draw, especially in finals" - en.wikipedia.org/wiki/Replay_(sports). It's not so disappointing when you know in advance it's a possible outcome. Nov 11, 2020 at 7:12
• @Falco .... and then end in a draw. Nov 11, 2020 at 9:45
• You know the maximum length of a cricket match before it starts. And 5-day test matches where one team has to spend a whole day (or longer) playing to avoid defeat, and the match finally ends in a draw, can be some of the most exciting games to watch for spectators who understand what is going on. Nov 11, 2020 at 13:35