The was a battle during the Sengoku period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

 (16th century) of Japan.

Marune was a frontier fortress in the possession of Oda Nobunaga

Oda Nobunaga

was the initiator of the unification of Japan under the shogunate in the late 16th century, which ruled Japan until the Meiji Restoration in 1868. He was also a major daimyo during the Sengoku period of Japanese history. His opus was continued, completed and finalized by his successors Toyotomi...

. Tokugawa Ieyasu

Tokugawa Ieyasu

 was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara  in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...

, who was at the time a forced retainer of the Imagawa, captured the fortress as part of the Imagawa advance that led to the fateful Battle of Okehazama

Battle of Okehazama

The took place in June 1560. In this battle, Oda Nobunaga defeated Imagawa Yoshimoto and established himself as one of the front-running warlords in the Sengoku period.-Background:...

 in 1560. Throughout Ieyasu's siege of this castle, he made good use of concentrated arquebus

Arquebus

The arquebus , or "hook tube", is an early muzzle-loaded firearm used in the 15th to 17th centuries. The word was originally modeled on the German hakenbüchse; this produced haquebute...

 fire. During the siege Sakuma Morishige

Sakuma Morishige

was a Japanese samurai who served Oda Nobunaga.In 1560, during the invasion of Owari Province by Imagawa Yoshimoto, leading up to the Battle of Okehazama, Morishige was appointed to defend the Marune fortress on the border of the province. The fortress came under attack by Tokugawa Ieyasu...

, the commander of the fortress, was killed by a bullet.