Meta: Maybe I was too wiki (in creating the NegativeKomi page). Didn't yet know about alias pages - thanks, Charles. You got my intention, but after I slept over it, I'm not sure if alias (in the is same sense) is appropriate any more (not meaning to change it). The reason is because reverse komi is sort of a unit or compound term (e.g. 5 points reverse komi = -5 points komi), whereas negative is an adjective about komi without changing its modus operandi (e.g. the komi is negative = Black gives negative points). To try to bring it to the point, reverse komi always is given by White - but nothing is said about its sign ("+" being intended, of course) - whereas negative komi is given by Black - as komi always is - and happens to be negative. That's why I fuzzed around again. Hope the confusion is complete now. :-)
Charles Almost: I think if many people used this I style confusion would become complete. Welcome, anyway. Minor editing, including copy-editing, tends to happen here without notice - this implies no criticism, of course. Very little is deleted, though. We like contributions to be signed: one good reason is that home pages usually give a grade.
Robert Pauli: Charles, you made a great job!
old discussion moved from main page
Robert Pauli: Instead of speaking of reverse komi one can also allow the value of (normal) komi to drop below zero, e.g.
To give Black 6 points is, of course, the same as "giving" White -6 points (I know I'm being silly here).
Now that we allow the full range, it would be more logical to turn the sign of komi (at least in my opinion). To increase a handicap would then either increase the number of handicap stones or increase the komi (or increase both).
Andre Engels: Negative komi is mostly used at smaller board sizes, because a more fine-grained difference is needed - between two players n stones on 9x9 might be clearly better than 50% winning for White, but n+1 clearly offer better chances for Black. Depending on the more exact differences, they could then play n+1 stones with komi for White or n stones with reverse komi.
Robert Pauli: Actually, negative komi should be used on the 19x19 as well, Andre. In fact, every handicap game should have negative komi - provided the ranks are one stone apart and handicap stones lack synergy (behave linear):
gap = 0 -> "handicap" 0.5 = place 0 and receive 6 (i.e. give -6) gap = 1 -> handicap 1.5 = place 1 and receive 6 gap = 2 -> handicap 2.5 = place 2 and receive 6 ...
Andy: I'm not a big fan of reverse komi. It is possible for the weaker player to blunder away stones and territory, but the reverse komi never goes away, even against perfect play.
RiffRaff: I think that's at least partially the idea. I've heard some stronger players mention that they like to play with reverse komi instead of handicap stones when they want to work on their Fuseki. Besides, even Go Seigen used it in playing against amateurs: http://www.gogod.co.uk/NewInGo/19800720_1.htm.