I'm trying to properly account for the movement of a large creature in D&D 5e, playing on a square grid. The creature needs to move through a double-wide doorway and then move to its right, effectively a movement around a corner. I'm aware of the rules for corners:

Corners. Diagonal movement can’t cross the corner of a wall, large tree, or other terrain feature that fills its space.

The crux of my question is what point or area "can't cross the corner". Borrowing the grid example from this answer, assume the large creature has passed through a doorway and is occupying squares B2, B3, C2, and C3. It needs to move to squares A3, A4, B3, and B4.


It would take one square (5ft) for a medium creature to move from B2 to A3, B3 to A4, or C2 to B3. Moving from C3 to B4 would require two squares (10ft). Does the majority apply, or the most limiting? I've reviewed several questions here but still think there's room for interpretation either way.

This answer is about hostile creatures, not an obstruction like a corner, but implies it's the center of the creature's square that's relevant for movement:

There is no recognition of the longer path between two diagonal centers than between two truly adjacent centers.

A liberal interpretation would imply the creature's center is already past the corner (between rows B and C) and would not encounter this obstacle. Only if the creature fully filled all 4 squares would it's "southeast" appendages encounter the corner.

The following picture represents the specific in-game situation. The yellow line (10 feet distance) crosses the corner and would result in 20 feet of movement according to the "corner rule". However, the green line is 15 feet of movement, with the middle segment the one relevant to this question. The green line does not impact a corner; in fact, it's 3.5 feet away from it. A creature 7 feet wide would not impact it.

enter image description here

Most convincing to me is a visual interpretation. The rules are unambiguous for the situation on a 5-foot grid of moving between green squares with the red square representing an something that "fills its space":

sample diagonal movement corner rule

However, consider this same 5-foot grid, but the obstacle in the red square does not fill its space, taking up only half of it:

sample diagonal movement corner rule not filing space

Since in this case the obstacle does not completely fill the space, I believe the "corner rule" doesn't apply, and RAW would only require 5 feet of movement.

Now, consider the specific question asked regarding a large creature. Scaling the above situation up by 2x we see the following on a 5-foot grid:

sample diagonal movement corner rule not filling space scaled up 2 times

If the previous 5-foot "does not fill the space" resulted in 5 foot movement, then this scaled up interpretation would imply a movement between the two green 10-foot squares would only require 10 feet of movement; the first half of which is the specific example in this question.

Given the above examples, does this movement require one square (5 feet) or two squares (10 feet) of movement?

I'd prefer a RAW interpretation if it exists, a RAI otherwise.


2 Answers 2


You can't do it directly, without making a sacrifice, but arguably, the squeezing rules could be used

No, the creature doesn't fully occupy a 10'x10' area. A medium creature doesn't fully occupy a 5'x5' area. But for the purposes of the game, they both travel through the whole of the area, and the corner rule forbids this.

That said, the squeezing rules could arguably apply here. They're written for when a creature is too large to fit at all, and that's not the case here, but if the creature is highly motivated to avoid a particular square, you could use the squeezing rules to simulate it pressing itself against the corner, weakening its position for combat in exchange for the slight improvement in movement flexibility (it won't let it travel further though; the squeezing rules cost movement). In that case, you could treat it roughly as if it was moving from C2 to B3 (or either of the other two squares it originally occupied that wouldn't violate the corner rule) as a medium creature, rather than occupying all four squares during the movement.

The cost is the squeezing rules themselves:

While squeezing through a space, a creature must spend 1 extra foot for every foot it moves there, and it has disadvantage on attack rolls and Dexterity saving throws. Attack rolls against the creature have advantage while it's in the smaller space.

So it would cost 10' of movement to move diagonally one square, rather than 5', and if it triggers an attack (opportunity or some other reaction), the attack will have advantage, or they'll take disadvantage on a Dex save, etc. That's actually pretty reasonable; if you're mid-combat and throw your back to the wall to sidle into a room, you'll have a harder time moving, dodging, etc., and the squeezing rules simulate this adequately.

  • \$\begingroup\$ You can also add that rules define the area that monster control as also an required area for it to fight effectively, if the monster moves cutting a corner then it is vulnerable as it does not have enough space to move away from the upcoming attack or other things that can limit its movement and this support using double movement when moving through such spaces. \$\endgroup\$ Jan 29 at 8:39

Diagonal movement from C3 to B4 is not allowed

From the rule you quoted, this is crossing a wall that fills a space (the unnamed C4). Any creature that is trying to move from C3 to B4 has to go to B3 first no matter what their size is. This takes 10 feet of movement.

  • \$\begingroup\$ But the creature is not 10x10. That's just the area it "controls". It's going to be smaller. The creature is not "in" C3 going to B4, its "in" some space with a center is on the intersection between the adjacent squares, and a line between those two intersections does not cross the corner. I think I need to add some pictures to my question to clarify things. \$\endgroup\$ Jan 26 at 22:27
  • \$\begingroup\$ @DanielWiddis I don't think that really matters since the rules define large creatures as 2x2 squares and outlines the rules for movement using that definition. If you would rule differently based on what you're saying, that may be a worthwhile answer. (Its okay to self answer) \$\endgroup\$
    – Jason_c_o
    Jan 27 at 3:19
  • \$\begingroup\$ @Jason_c_o I've added some pictures to the original question to make it more clear. I think the real crux of the interpretation is whether movement is based on the center (as the linked question moving diagonally between two enemies does not encounter either of their "terrain") or some other "width". I'm more inclined to accept the answer with "squeezing" as the best RAW interpretation since it seems to specifically acknowledge a creature's width. \$\endgroup\$ Jan 27 at 6:22

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