Large vs Reach

[MR CRITICAL]

If you hav a reach weapon like a spiked chain which gives u 10ft reach then how much reach will u hav if someone cast Enlarge person on u to make yourself bigger ???

[zza ni]

"Large or larger creatures using reach weapons can strike up to double their natural reach but can’t strike at their natural reach or less."

from the combat section about smaller and bigger creatures.
so if he has 10 ft nat reach and using a reach weapon sized for him, he would have a reach of up to 20. if he has 15 it's 30 etc.

(note the rule about not being able to strike closer is for striking with the reach weapon, and that should also only be with reach weapons that are unable to hit closer, so stuff like whips should work as usual)

[Pizza Lord]

Let me ask you something
Does the spiked chain give you reach?

But in answer to the basis of your question, if you have a reach weapon (sized appropriately to you, so no dual-wielding a 'normal' weapon and a Tiny-sized longspear for both normal and reach threatening), the rule is that you double your natural reach. Now, there's some dev disagreement on if this should have an exception for creatures with '0' reach, because they don't actually have zero feet reach, just not a reach in 5-foot squares) to allow them to have a 5-ft reach, but that's not the issue here).

If you have a reach weapon, you double your normal reach but can't (usually) attack within that distance.

In the case of a whip, you have 15-foot reach and can attack any target within that range, but that's a special case and it works as a ranged attack and a melee attack, rather than a true, baseline reach attack (nor do you threaten).

A Medium-sized (tall) combatant with a reach weapon can strike targets out to 10-feet (2 squares) away, and they don't count the diagonals as 15-feet, (they did at first, because they were dumb and short-sighted). If the creature was increased to Large size (normally a 10-foot reach), and assuming the weapon sized appropriately (which most effects will do), then they'd be able to strike targets at 15 and 20 feet, but not at 10 feet or closer.

[Diego Rossi]

Pizza Lord wrote:

Let me ask you something

Does the spiked chain give you reach?

It doesn't, it was a 3.x SQ that wasn't ported into Pathfinder.

[Melkiador]

In 3.5 the spiked chain was often considered to be too good. I think Pathfinder nerfed it too far the other way. But maybe some tables still use the old 3.5 version.

This is how the 3.5 version worked:

Quote:

A spiked chain has reach, so you can strike opponents 10 feet away with it. In addition, unlike most other weapons with reach, it can be used against an adjacent foe.

You can make trip attacks with the chain. If you are tripped during your own trip attempt, you can drop the chain to avoid being tripped.

When using a spiked chain, you get a +2 bonus on opposed attack rolls made to disarm an opponent (including the roll to avoid being disarmed if such an attempt fails).

You can use the Weapon Finesse feat to apply your Dexterity modifier instead of your Strength modifier to attack rolls with a spiked chain sized for you, even though it isn’t a light weapon for you.

So, not only did it have reach, but it also didn't have a dead zone. If that version existed in Pathfinder, you'd have a large humanoid threatening everywhere within 20 feet with it.

[MR CRITICAL]

A Hammer Lucerne has reach and if he Enlarge person the reach whd be ???

[Melkiador]

Assuming no other means of threatening, the person would threaten at 15 and 20, but not threaten at 5 or 10.

It's not unusual to use a second weapon to threaten within those closer areas. Improved Unarmed Strike is the most accepted way of doing this, but something like armor spikes may also allow multiple ranges of threatening with some people arguing against