Ruy Lopez that after the common retreat 4.Ba4, Black will have the possibility of breaking a future pin on his by playing ...b5. White must take some care not to fall into the Ruy Lopez, Noah's Ark Trap, in which Black traps White's on the b3-square with a ...a6, ...b5, and ...c4 pawn advance on the . Ercole del Rio, in his 1750 treatise "Sopra il giuoco degli Scacchi, Osservazioni pratiche dell'anonimo Modenese" (On the game of Chess, practical Observations by an anonymous Modenese), was the first author to mention 3...a6. However, the move became popular after it was played by Paul
Tactical decision game Tactical decision game A tactical decision game is a decision game that puts students in the role of the commander of a tactical unit who is faced with a challenging problem. While most tactical decision games depict problems faced by the commanders of military units, a growing number deal with the situations of types dealt with by police and firefighting organizations . The tactical decision game is known by a variety of names. These include "map problem", "tactical problem", "one-step war game", and "tactical decision exercise". Like other types of decision games, tactical decision games may either be historical or