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
War and Peace (game) commanding general's box, reducing clutter on the map), while the alliance chart, force pools, and prisoners are on the campaign game card. Player sides are: France (blue), Spain (yellow), Britain (red), Austria (white), Prussia (gray), and Russia (green). The markers for Fortresses, entrenchments and demoralization are black. Tactical matrix markers (see below) are white. Strength points are also rated for what the game calls "morale" (a proxy for troop quality). Militia, landwehr, partisans and cossacks rate "0". Regular infantry (yellow lettering for minor countries, or black for Prussian, Austrian or Spanish regulars) rate "1". British, Russian and French infantry (white