A pawn that is not opposed by an enemy pawn either on its own file or adjacent files.
ECHESSPEDIA
Quotes of the Day
I think the players in this world championship are in different leagues. Karjakin is excellent—Carlsen is special.
Garry Kasparov 2016
Now, at 51, in my life I have reach the stage between the middlegame and the endgame. But I don’t have the feeling that I am in the endgame already.
Boris Spassky 1988 NIC
Not this time, Mr. Carlsen! (after winning the World Blitz Championship 2016)
Sergey Karjakin 2016
If I’m thinking for more than 20 minutes about one move, it’s usually a waste. Sometimes you can come up with some amazing solution but most of the time you just end up looping: you consider a move, you reject it, then you’re desperate, you come back to the move, you don’t remember why you rejected it, you have to make a move so you make it – then your opponent replies and you remember why you rejected it. The longest wait I ever did between moves was one hour and five minutes – and the move was horrible.
Magnus Carlsen 2016
After the 2nd game I could have returned to Moscow. There was only one way I could have won this match.
Boris Spassky (1974)