One of my sons once won a prize for biggest upset in a tournament. I think it was a500 or 600 point differential. Of course, my son was probably slightly under-rated since he had only just started playing. Also at lower ratings, players can make big blunders that even players several hundred points lower can take advantage of. GMs rated 2700 make few mistakes, and their mistakes are rather subtle.
Rasparovov wrote:
tieics wrote:
I think if there is 300 ELO point difference between two players it's no point playing the game. Practically the player with lower ELO has 0 winning chance.
I won against a guy rated 509 points ahead of me. With black. After 23 moves.
It's possible of course, but so probabilistically unlikely it would almost never happen ever in real life unless the GM falls asleep and loses on time or something. The 1300's best chance would be to memorize some completely obscure not known at all trap opening, and even if the GM has never seen it before 99.999999% of the time they will not fall from it just because of their instincts and ability to see far ahead.