# In a four person game of Quoridor, can a player be forced to pass a turn?

As a follow up to my question earlier, can a player be forced to skip a turn when playing a four player game of Quoridor? The rules state that a pawn cannot jump over more than one pawn when moving, but this brings up an potential board state in which a player has no valid moves:

Suppose the turn order is Green, Red, Blue, then Yellow. Green started on the west edge, Red started on the north edge, Blue started on the east edge, and Yellow started at the south edge.

It is Blue's turn, and Yellow has already used all of its walls. Blue then traps all four pawns in the tight corridor by placing its final wall horizontally immediately south of it (noted here by the faded wall below Yellow and Blue). It is now Yellow's turn, but Yellow has no walls, nor does it seem that it has any valid moves. Furthermore, if Green and Red place walls on their next turns, Blue and Yellow are potentially trapped again.

What is the proper way to handle this circumstance?

• Ooh, good catch! Has this scenario actually come up for you? My guess is that it's rare enough that the game creators either didn't think of it or didn't bother writing a rule for it. I'd just add one of the following house rules: 1) Blue's move is illegal or 2) Yellow skips her turn. Aug 3 '16 at 23:51
• Thanks! There was something similar that happened the other day, all four pawns we packed into a corridor and it got me wondering how something like this ought to be handled. Regarding the house rules, there are also ways something like this could come up without walls needed to be placed, which would then imply restrictions on movement, too, something along the lines of "if pawn movement or wall placement prevents a player from having any valid moves, that action is illegal". That said, it'd be nice to find something more definitive :D Aug 4 '16 at 16:47
• Oh, this can actually chain multiple turns: A's move can become illegal because it leaves B with only one move that is illegal because it would leave C with no moves. At this point I'd scrap that house rule: it should never be that complicated just to figure out what's legal. So instead I vote for the skip-your-turn rule. Aug 4 '16 at 17:27
• @ikegami I know that e.g. chess calls it a draw when you can't move, but that seems really awkward in a 4 player game - the actions of 3 of the players can force the 4th into a draw?! (Imagine green was instead at R1C8 - it's not her fault the other three players are derping around in that dead end) Aug 4 '16 at 17:29
• @ikegami I agree that if it happened without prior agreements, as you write in your answer, among competitive people it'd be too late to choose a house rule and you'd have to take the most commonly accepted meta-rule: the game is a draw. But unlike in say chess or MtG where that meta-rule is also both officially in the rules and a reasonable way of resolving the situation, here it is neither, so it is definitely worthwhile to come up with a house rule. I'd even get the group to pick one on the spot if I was in a friendly group - no reason to terminate a perfectly fine game. Aug 4 '16 at 18:32

I would call this game a draw because there are no legal moves available to Yellow. Choosing how to resolve this on the spot would be unfair.

However, it is possible to come to an agreement to a solution before the game starts.

In a two-player game, this problem is addressed by allowing one to jump over an opponent.

``````Valid moves for "A"
╬═════╬═════╬═════╬═════╬
║     ║  ◎  ║  ◎  ║     ║
╬═════╬══╪══╬══╪══╬═════╬
║  ◎ ─╫─ A ─╫─ B ─╫─ ◎  ║
╬═════╬══╪══╬══╪══╬═════╬
║     ║  ◎  ║  ◎  ║     ║
╬═════╬═════╬═════╬═════╬
``````

If I wanted to create a house rule to address this problem in four-player games, I'd simply extend the jumping rules.

``````Valid moves for "A"
╬═════╬═════╬═════╬═════╬═════╬
║     ║  ◎  ║  ◎  ║     ║     ║
╬═════╬══╪══╬══╪══╬═════╬═════╬
║  ◎ ─╫─ A ─╫─ B ─╫─ ◎  ║     ║
╬═════╬══╪══╬══╪══╬══╪══╬═════╬
║     ║  ◎ ─╫─ C ─╫─ D ─╫─ ◎  ║
╬═════╬═════╬══╪══╬══╪══╬═════╬
║     ║     ║  ◎  ║  ◎  ║     ║
╬═════╬═════╬═════╬═════╬═════╬
``````

These movement options would be allowed at all times, not only when no other options are available.

• The only catch with the house rule presented is that the official rules very explicitly forbid jumping over more than one pawn in a single move. This is referenced in figure 10 of the rules I linked. Aug 4 '16 at 22:15
• Yeah, I think the figure 10 rule is important for balance - jumping a long distance is extremely powerful. While I'd consider house-ruling OP's situation to allow a long jump like that, it does not make sense to me to upset the normal balance of the game by always allowing such jumps. Aug 5 '16 at 0:05
• Also, note that the normal rules are actually more complicated than what you've shown - you can only do a "diagonal" jump if the straight jump is blocked by a wall. So if you want to extend jumping to multiple players at once, you'd either need a potentially-complicated extension of that 2-player jumping limitation, or you'd need to make it even more powerful by actually allowing all the jumps you've shown without limitation. Aug 5 '16 at 0:07
• Re "The only catch with the house rule presented is", That's not a catch. If the ruled allowed it, there would be no point in creating a house rule. Sep 6 '16 at 22:18
• Also regardless of whether we allow the diagonal jump when blocked by a player as well as a wall, your diagrams are still oversimplifying matters: there is no situation in which all 6 moves in diagram 1 would simultaneously be legal, since we both agree you have to be blocked by something to take a diagonal jump. Similarly, canonicalizing your second diagram would require it to be accompanied by a text rule explaining which of those 8 moves are legal at any given time - can you write such a rule succinctly? Sep 7 '16 at 0:34

Positioning of the fences

• The fences must be placed between 2 sets of 2 squares

• The fences can be used to facilitate the player’s progress or to impede that of the opponent, however, an access to the goal line must always be left open.

So blue can't place a fence here 'cause it will block the path to the goal line

• Well, if ever there was a definitive source on the rules of Quoridor, David Gigamic would be the guy. Thanks for your help! This circumstance could also come about based on players taking moves, would those moves then be illegal? I would be happy to post a visual example if that would clarify things. Aug 8 '16 at 18:17
• @Robby I wouldn't be so quick to accept this answer, even from David Gigamic. Not only is it already stretching the no-blocking rule beyond how most players would read it, but as you point out it's also easy to come up with similar scenarios this doesn't answer, including ones that don't involve placing fences at all. Sep 1 '16 at 0:55
• Hi Benjamin, i made a quick answer for your other problem :) Sep 1 '16 at 15:05
• Thanks! To me that answer confirms this one is unnecessary: if a player can be forced to skip their turn, that seems like the easy solution here. The simplest reading of "access to the goal line must always be left open" (and the only reading directly supported by Fig 5) is that the walls themselves must not form a permanent barrier between a player and the goal. Here you read in more to that rule: that the walls together with the current configuration of pawns (and possibly the turn order?) must also not form a temporary barrier. Sep 1 '16 at 17:29
• This answer makes no sense. Access to the goal line is present to all players in the OP's scenario. Some of them are simply not able to head towards it this turn, which is actually a very, very common situation. Sep 6 '16 at 21:57