No mating material shouldn't win

Opponent only has a bishop left - should have been a draw:

http://en.lichess.org/nG1jNykyMMvw

FIDE chess rules, article 9.6 - "The game is drawn when a position is reached from which a checkmate cannot occur by any possible series of legal moves. This immediately ends the game, provided that the move producing this position was legal."

http://www.fide.com/fide/handbook.html?id=124&view=article

lichess.org/editor/5k1K/7R/5b2/8/PP6/8/8/8%20w%20- Checkmate.
Regardless how unlikely it is that your opponent will let you achieve this position, it is doable with a "possible serie of legal moves". So, black wins.

I think you have the wrong emphasis here - on most established blitz servers, if someone doesn't themselves have mating material, it shouldnt count as a win on time - only a draw with "insufficient material". The emphasis you have right now encourages quite bad etiquette.

Just having a knight or bishop left, should just be a draw IMHO as far as online blitz chess is concerned.

Best wishes
K

Oops, my example was wrong. This one is better lichess.org/editor/8/7R/8/8/8/2b5/P7/K1k5%20w%20-

But black does have mating material. It *is* possible to checkmate white from the current situation.

FIDE rules may not be the best, but they are widely recognized and accepted. If lichess doesn't follow them "à la lettre", it's gona be a mess, and a lot of people will contest the rules.

I know but it shouldn't be with a view of helpmates - it should be your own material for mating purposes. Seriously if you check out most established blitz servers I think they have this in place - it is only ones own mating material that counts. It might not be strict according to FIDE rules but FIDE is based on OTB chess - not online chess, and you should feel free to adapt it to online chess.

Seriously if you want in the future more titled players playing here, then I would suggest you only count mating material when someone has it. It could be a pawn on its own - that is mating material too. A rook. A queen. But not either a bishop on its own, or a knight on its own. Most titled players online play on either ICC or Playchess. If they come here and find this rule for basicially favouring winning many games on time when the opponent themselves have not got matiing material, I really think this will be a major put-off.

Just to clarify a bit - the person with the single knight or bishop should be able to play on as there is a theoretical win if the opponents material supports a mate - but they shouldn't be able to win on time.

Thibault, your example was was wrong again. Pawns don't move back. This one is right. The mate is possible. Black wins.
http://ru.lichess.org/editor/8/8/1bk5/1R6/PP6/7K/8/8%20w%20-%20-%201%2060