Exposition on a battle on a flight of stairs, using the GURPS rules

[Ulzgoroth]

Originally Posted by Pursuivant

Then RAW are wrong.

If you've got a long "pole weapon" and you've "choked up" on the grip, you'll have a lot of the haft behind you. That "extra" length will get in your way in close quarters.

You've made a very generous expansion of evileeyore's brief statement. Especially so since 'choking up' on the grip is your own injection to the subject. Weapons, as you surely know, have minimum reach, and there are specific rules (not, by the way, Defensive Grip) if you're looking to employ it at a shorter distance.

Originally Posted by Pursuivant

I'd suggest that you need a horizontal distance of (weapon length + 3') between you and your target, and you and whatever obstacles are behind you, in order to effectively use a polearm or spear in a narrow space. Anything less than that gives you a -3 penalty to hit or to defend per missing foot of distance, assuming the GM allows the attack at all.

This is, in fact, vaguely reminiscent of the full rules - but not particularly necessary to the discussion that was taking place.