It is also called the Sunomata Ichiya Castle (墨俣一夜城), due to the legend that it was built in one night.

"The work of building at Sunomata was done by a band of adventurers under the direction of a local robber baron named Hachisuka Koroku.

"[1][2] Hideyoshi used pre-constructed sections to put up the fortress and it was finished so quickly that it gave the impression that it was done overnight, although the work took several days to complete.

Hideyoshi's success with the construction of this castle greatly raised his prestige and standing with Nobunaga, and marked the start of his rise to fame.

In reality, it was more of a border fort than a full sized castle, and was intended to intimidate, surprise and demoralize the enemy.