What would approximately be the ICCF rating of a GM with no external help and of a computer with no human judgment? I need some players who play at the ICCF (International Correspondence Chess Federation) to answer this question.

What would approximately be the ICCF Elo rating of the two following players?


Player A is a Grandmaster with an OTB rating of 2500 Elo FIDE. He will not use any engine, nor will he use any opening database, nor will he use any opening book, nor will he use any endgame tablebase, nor will he use any form of outside assistance. He will play using only his brain. He will use on average about 5 minutes per move, which also happens to be the average time per move of humans in OTB chess at classical time control. Player A is 100% human.
Player B is in reality a patzer, with an OTB rating of 1200 Elo FIDE. For the opening he will use an opening database and in each position he will just pick one of the popular moves which score well. For the rest of the game, he will use one (and only one) of the top 3 best engines: Komodo 9, Stockfish 6 or Houdini 4 (64-bit version). His engine will have 7-men endgame tablebases. At each position he will let his engine run for one hour (using 4 CPUs) and then he will blindly pick his engine’s first suggestion. He will not offer draws or accept draws early, he will continue his games until it is very clear that the position is a draw. He won’t resign early either, he will wait until he gets checkmated. Player B is 100% computer.


Note that I only need an approximation. But still, try to make your approximation as accurate as possible.
I play on ICCF. My guess is that the engineless GM might be able to maintain a 2000 rating by beating other engineless players or players who are bad at engine use.

I don't think the second player would do that well actually. Players in the 2300+ range are all using anti-engine strategies, following GM opening theory, have their novelties, so they can lure him into opening traps or positions his engine has trouble evaluating. I would guess he'd wouldn't go much beyond 2100.  I've played against 2200 players who are pure engine once out of book, but they put more effort into their openings than your player B does.

There is another breed of player you haven't mentioned: the engine monkey master.  These are players with 2000+ ratings over the board. They could potentially try to carry out strategic plans in the middlegame, but they get so caught up in the engine analysis they end up play positionally suspect moves. They do contribute a lot to the openings and endings though, so you see them in the 2300-2400 range.