Diagonal Weakness of Polearm Sentinel?

[Cespenar]

So, let's say your Polearm Master Sentinel is not in a 10 ft tunnel. Can't enemies approach from the diagonal squares, effectively getting 5 ft within your fighter and are allowed to attack you? Yes, you'd still get your opportunity attack, but you can't just lock down their whole round like it's usually done.

If yes, how commonly would you utilize this against your players as a DM? Would this effectively be considered basically as a tactical maneuver that enemies with above average intelligence would use, or would you let everyone use this against your fighter?

[Giant2005]

If a diagonal 2 squares away counts as more than 10', then the diagonal 1 square away would count as more than 5' and you wouldn't be able to attack from there.

[Arial Black]

If you use a square grid, and have each second diagonal count as 10 feet, you also need to adopt the 'reach weapon exception', which allows weapons with a 10 foot reach to also be able to attack those 10 foot corners (which would ordinarily count as 15 feet away).

This was the case in 3E, where the square grid/reach weapon rules first appeared. In 4E they used 'squircles' by not having the 'second diagonal is 10 feet' rule at all.

If you don't use the 'reach weapon exception', then you will....encounter the very sort of problems that you describe!

So, use it!

[Gwendol]

In 3e you always reached two diagonal squares with a 10' reach. It was a special rule. Since 5e assumes TotM, rules at tables can differ, but my recommendation would be to keep the 3e rule.

[Fighting_Ferret]

The grid is just an approximation... a character armed with a polearm weapon with the reach property can threaten anything within 10 feet of their current location. The fact that a diagonal takes 10 feet to move across on a grid stems from the 5 foot square actually having a 7 foot diagonal, which is why the every other square of diagonal movement costs 10 feet cropped up as a better solution.

If it is withing 2 squares of the one you are currently occupying, then you can attack it, as you can reach the square it is in. The creature cannot pick what part of the square(s) it occupies... it occupies all the space in those square(s) and you can reach 10 feet, which means you can reach all those squares.

Now for the funny part.. we always ask what we can do/ get away with, but we pay little mind to limitations. You had initially set up a 10 foot tunnel, which brings up an interesting question... how much room is required to swing that 10 foot reach weapon, and do you have enough clearance to do so effectively?

[Slipperychicken]

I'm pretty sure the "every other diagonal counts as 10ft" thing only applies to movement.


The "variant: playing on a grid" sidebar in PHB 192 doesn't penalize reach that way. A 10ft reach weapon goes out 2 squares in every direction.

[gfishfunk]

"We'll approach from the North-East, to limit the range of their halberds."

[Fighting_Ferret]

I'm pretty sure the "every other diagonal counts as 10ft" thing only applies to movement.
The "variant: playing on a grid" sidebar in PHB 192 doesn't penalize reach that way. A 10ft reach weapon goes out 2 squares in every direction.

Thus my second point...
If it is withing 2 squares of the one you are currently occupying, then you can attack it, as you can reach the square it is in. The creature cannot pick what part of the square(s) it occupies... it occupies all the space in those square(s) and you can reach 10 feet, which means you can reach all those squares.

[MaxWilson]

So, let's say your Polearm Master Sentinel is not in a 10 ft tunnel. Can't enemies approach from the diagonal squares, effectively getting 5 ft within your fighter and are allowed to attack you? Yes, you'd still get your opportunity attack, but you can't just lock down their whole round like it's usually done.

If yes, how commonly would you utilize this against your players as a DM? Would this effectively be considered basically as a tactical maneuver that enemies with above average intelligence would use, or would you let everyone use this against your fighter?

As a DM I'd feel obliged to switch to a finer granularity (whether infinite-resolution grid or theatre-of-the-mind) rather than produce an unrealistic result based on 5' grid squaring. Normally 5' grid squares are reasonably okay but in the Polearm Master Sentinel case clearly they aren't.

In short: the attack would still happen at 10', which means it happens between 5' grid squares on the diagonal, so the enemy stops partly between squares.

[Segev]

There's always the option of switching back to war-gaming roots of D&D, and measuring distances with a ruler or tape measure or string. Use templates for simplicity.

It works fairly well in Warhammer (Fantasy and 40k). And 5e is more friendly towards it than 3e or 4e were.

[Cespenar]

So, the consensus is probably to use 2 squares in all directions. Good.


"We'll approach from the North-East, to limit the range of their halberds."

I was liking this solution though. :smalltongue: