I know I am dredging up a dead thread here and committing a forum-necromancy-foul, but I must put the "origins" of the chanting of chair to rest.
SuperKawaiiNeko got it mostly right on page 1 that it began at Fanime 2000 (maybe 1999? my memory fails.) What is untold is the backstory, behind the curtain, backstage.
The Masquerade was indeed running late and the person running it that year asked someone for a distraction as the crowd was getting rowdy. John Hernandez (cosplayed as Tochiro with Michael Wright as Harlock a few times during the staff skit) had a chair handy. He put the chair on stage, chanting began. That's it. How do I know? I was there.
Sure there were chants before "chair", most popularly, "dance" at AX, but the Chair spinoff originated at Fanime. On a whim.

Photo taken by me of: (left to right) James "Matsuman" Matsuzaki (in the fur suit), Michael Wright (as Harlock), John Hernandez (as Tochiro) and some unknown Crossplayer.
SuperKawaiiNeko got it mostly right on page 1 that it began at Fanime 2000 (maybe 1999? my memory fails.) What is untold is the backstory, behind the curtain, backstage.
The Masquerade was indeed running late and the person running it that year asked someone for a distraction as the crowd was getting rowdy. John Hernandez (cosplayed as Tochiro with Michael Wright as Harlock a few times during the staff skit) had a chair handy. He put the chair on stage, chanting began. That's it. How do I know? I was there.
Sure there were chants before "chair", most popularly, "dance" at AX, but the Chair spinoff originated at Fanime. On a whim.

Photo taken by me of: (left to right) James "Matsuman" Matsuzaki (in the fur suit), Michael Wright (as Harlock), John Hernandez (as Tochiro) and some unknown Crossplayer.