Mantinea was an important battle in the Peloponnese War. It occurred in 418 BC between Sparta and its allies on the one hand, and an army led by Argos (the Argivos) and Athens on the other. In the simulation it will be considered the hypothesis of what might have been the final tactical result if the Argive left wing had been reinforced by exploring a technique similar to the oblique order (Battle of Leuctra, 371 BC). However, going a little further, it will also be considered how the confrontation would have occurred between a massive Argive device, with the phalanges of all wings in column (smaller front, greater depth), against an open spartan device (larger front, smaller depth). Thus, in the first instance, the premature flight of the less reliable wing would be prevented, in a second moment it would surprise the other side by applying a concentration of forces (elite troops) on the opposite side of the traditional one and, finally, delay the shock of the center and of the right wing, also reinforced (massed), contributing to the final imbalance of the opposing device.