Hydaspes River
At the Battle of the Hydaspes River in May of 326, BC, fought in what is now the Punjab between Alexander the Great of Macedon and the Indian king Porus, Alexander successfully carried out a brilliant military deception that wrong footed his opponent and caught him off guard, and set the stage for a complete Macedonian victory.
When Alexander marched into the Punjab, king Porus set out to intercept the invaders, and beating them to the Hydaspes river, which Alexander would have to cross to penetrate into Porus’ territory, the Indian king waited on the far bank with his army to prevent Alexander from crossing. When the Macedonians arrived, Porus set his camp across the river from Alexander, and shadowed the Macedonian’s movements from the opposite side, as the invader marched up and down the far bank in search of a safe crossing.
So long as Porus shadowed the Macedonians from the opposite bank, a crossing of the deep and fast-moving river could prove catastrophic if made against opposition, as the Indians would be able to strike the Macedonians at their most vulnerable mid-stream, or fall upon and overwhelm a portion of Alexander’s on the Indian side of the river, before the crossing was completed.
So Alexander set out to lull Porus by marching his troops up and down his side of the river each day. The Indians vigilantly shadowed those movements at first, but over time, became accustomed to them and grew complacent. Then Alexander quietly drew off the bulk of his army, leaving behind a contingent to make noisy demonstrations in order to keep the Indians fixated on them, while Alexander hurried to a crossing upriver and safely got his force across, unopposed. Once on Porus’ side of the Hydaspes, Alexander advanced to attack, and caught the Indians in a pincer between the main force under his command, and the smaller contingent left behind on the opposite side of the river to keep Porus occupied, which crossed the Hydaspes and fell upon the Indians’ rear and flank when they turned to face Alexander. The battle was hard fought, but the outcome was a total Macedonian victory.