Yeah, the AIs for the bots on, say, chess.com are really weird. Sometimes they’ll play brilliantly and other times they’ll let you trade into a dead-lost endgame. Isabel (1600) seems particularly guilty of this.
But you can see it with Nelson, too. If you know how to refute his attacks, he can start doing nothing quickly.
With people there are going to be swings, too, based on relative endgame/middlegame/opening strengths. And if someone is fooled into an opening they don’t know by transposition, you can often knock 300-400 points off their ratings.
Fatigue is also a factor. I can just miss stuff when I’m tired, a lot of wins of material or even checkmates I would probably pick up on. I’ve learned not to play when tired!
And sometimes it can just be hard to adjust to a weird change in fortune, even in your favor.
Oh. Hey. How about a game? From GM Gawain Jones’s King’s Indian course… I’m really impressed by his writing style.
Well, two games actually. He shows what can happen if White tries to play too slowly. Okay, White kind of slipped up big-time, but it’s not like their blunders were super-obvious.
1.Nf3 Nf6 2.g3 g6 3.b3 Bg7 4.Bb2 O-O 5.Bg2 c5 6.c4 d6
7.d4 d5 8.cxd5 Nxd5 9.Qd2 Nc6 10.dxc5 Nf4 11.Bxg7 Nxg2+
12.Kf1 Nh4 13.Bxf8 Bh3+ 14.Kg1 Nxf3+ 15.exf3 Ne5 16.Qe2 Qd4
Apparently it’s mate in 5!
end position 1
1.Nf3 Nf6 2.c4 g6 3.b4 Bg7 4.Bb2 O-O 5.g3 Nc6 6.a3 e5 7.Nxe5 Nxe5
8.Bxe5 Re8 9.Bb2 d5 10.cxd5 Qxd5 11.Rg1 Qh5 12.h3 Bxh3 13.Rh1 Qf3 14.Rxh3 Ng4
end position 2
No mate here but he notes White can’t stop Qxf2. d3 Qxf2 kd2 Bxb2 is just miserable.