[plfhxrud] One bit of assistance

Consider a chess game where one of the participants is permitted to receive 1 bit of assistance from a confederate (likely armed with a computer) during the course of a game.  Perhaps a light turns on (and stays on) after some opponent move.  The opponent does not get to know that the bit was sent.

How much is this 1 bit worth, in terms of Elo improvement?

Exactly what to communicate with that 1 bit should be decided as a protocol between confederate and player before the game (kind of like bridge).  One possible protocol could have the bit mean "opponent has just made a subtle mistake; you should look specifically for a punishing move."

This is a very limited form of Advanced Chess, but with only one player permitted extremely limited "use" of a computer.

The purpose of this exercise is to measure just how difficult preventing cheating in chess will be.  In a normal game, preventing the covert transmission of only 1 bit will be extremely difficult.