Flooding! The battle of Bicchu Takamatsu Castle

Okayama-city, Okayama A.D.1582
A relentless water attack. That is what the Hashiba army used to bring down the castle of Mori shogun Shimizu Muneharu. Hashiba had 25,000 men against only 3,000 from Shimizu. A simple frontal attack may well have brought them victory, but the swampland terrain around Takamatsu castle made any engagement difficult, leading to Hashiba's choice of a water attack. Not long before this, Akechi Mitsuhide had changed the course of history at Honno-ji temple, Kyoto (The Gekokujo, HonnĊ-ji Incident).
Highlights of the map Hashiba Family (pink) VS Mouri Family (blue)
May 1582. The middle of Japan's monsoon season. More than 3000m of dikes had been built to divert the Ashimori River nearby Takamatsu castle. It had been a swift operation taking only 12 days. It is said that local farmers were brought in to help and were compensated 100 mon and a sack of rice by the Hashiba army for each straw sack of earth.
Behind the scenes drama
Though Hashiba Hideyoshi wanted to return to Kyoto as quickly as possible after learning of the death of Oda Nobunaga, he had to stay to see Muneharu commit ritual suicide (seppuku) on a boat. This was Hideyoshi's condition if he was to spare the lives of Muneharu's men in the castle. It is said that Muneharu's seppuku was so splendid that it changed the way people committed seppuku from then on.