Okehazama

The Battle of Okehazama (桶狭間の戦い) is Nobunaga's infamous battle where he destroys the Imagawa army in one decisive battle. It shows the strategic workings of Nobunaga by using a very small force against the comparatively massive Imagawa army.

Samurai Warriors
In Samurai Warriors, it is a three-way battle including the Imagawa, Oda, and Tokugawa. Both latter clans fight for independence, and the player, if using Hanzō, may use the ninja path leading into the Imagawa main camp. Masamune also interrupts the battle during his story. In order to convince Ieyasu to defect to the Oda, players have to defeat Tadakatsu.

The battle is shown via cutscene in the second game. It returns in the Xtreme Legends expansion. In the Oda scenario, Hideyoshi leaves the field to find a path to ambush the Imagawa main camp, while Nobunaga lulls Yoshimoto into a false sense of security. Eventually, Hideyoshi reappears with some few peasants, and together they ride down a slope and attack the enemy commander. Unlike the previous version of the battle, the Tokugawa faithfully serve the Imagawa.

In Samurai Warriors 3, the battle remains relatively same except after Nobunaga's ambush succeeds, Yoshimoto tries to flee away from the field.

Kessen
Okehazama is the major battle that concludes chapter 2 in Kessen III. After dealing with his family and other enemies in Owari, Nobunaga's forces are faced with Yoshimoto's massive army along their border. Though facing the opposing odds, the young leader merely naps after judging the consequences of fighting or surrendering. During the night before they ride out to battle, Tokichiro introduces the weather-reading girl, Yoshino, to his master. She foresees a rain storm the following day, which Nobunaga uses to his advantage whilst planning.

On the map, the ally army is split into two forces. One side protects the ally camp in the east, facing the onslaught of Motoyasu, Tadakatsu, and other fierce Imagawa generals. Nobunaga and Yoshino are stationed in the west, a forested and mountain path that opens more opportunities for their march as it rains on the field. In essence, the general plan of the battle is to have the three eastern units take a sturdy defense while Nobunaga's formation moves through the mountains. The shorter time limit and the necessary condition of protecting the ally camp are the main reasons for this strategy. Once an enemy unit in the east is defeated, the downpour will begin and Nobunaga can discreetly move his army through the forested area. Yoshimoto laments at the rain and separates himself from his army to have a reprieve from the battle.

To have the ambush succeed, Nobunaga must defeat Yasumoto Asahina, the enemy general who sees them in the mountain path. Preventing his speedy report to Yoshimoto can ensure that the ambush will work. He retreats quickly from the mountains, so it's ideal to stop him before he crosses into the main field. If he is defeated in time, players may choose to end the conflict quickly by surprising and dispatching the enemy commander. If the enemy general reports his sighting, Yoshimoto and his three closest generals will be alerted to Nobunaga's position and will stand firm together, making it harder to end the conflict.

If players defeat Sessai Taigen, he will join Nobunaga's forces after the battle. He can be routed by either the eastern or western fronts as moving to defeat him will not spoil the ambush.