Azai Nagamasa was the lord of North Oumi(current Shiga prefecture) in the Sengoku era.
Azai Hisamasa who was Nagamasa's father obeyed Rokkaku clan who was the lord of South Oumi.
However the vassals of Azai clan disliked this obedience, they made Hisamasa retire, and then Nagamasa became Hisamasa's successor.
Nagamasa broke with Rokkaku clan, and entered into an alliance with Oda Nobunaga by marrying Oichi who was Nobunaga's younger sister.
(Oichi married Shibata Katsuie who was the chief vassal of Nobunaga after the perish of Azai clan.)
Nagamasa is known as a strong SAMURAI.
He led the military at only 15 years old and He showed a great talent of battles.
When Nagamasa was allied with Nobunaga, Nobunaga promised that he would inform Azai clan in advance when Nobunaga attacked Asakura.
(Azai clan had been allied with Asakura clan before that.)
However Nobunaga broke the promise, he attacked Asakura clan.
For that reason, Nagamasa betrayed Nobunaga, and attacked him with Asakura clan.
As a result, Azai and Asakura clan were defeated.
There is a legend that Nobunaga led his subordinates to make cups using Nagamasa's skull, and drank sake at that time.
However some people say that the legend was a fiction.
