What is the 5...Ng6 Retreat Variation?
To start, White moves this pawn forward
Black counters by moving this pawn
White brings the Knight here
Black replies by moving this Knight
White counters by moving this Knight
Black responds by placing the Knight here
White takes this pawn
Black takes the Knight
White moves his pawn forward
Black retreats the Knight to g6
This is the 5...Ng6 Retreat Variation