The story begins in the village of Toyone, part of the Mikawa province at that time. The Mikawa province was under the rule of the Imagawa.
The nearest village is Tobishima.
The neighbouring province, Owari - under Oda rule - had poor relations with the Imagawa, and in June of 1560, the went to war. A famous battle took place: the Battle of Okehazama. In this battle, the Oda managed to defeat the Imagawa force of 25,000 men, despite only having 2,500. It is one of the most brilliant military successes in history.
Oda Nobunaga - the Daimyo at the time of the battle - was a very young man, and went on to unify all of mainland Japan. Dying before he managed to unify the surrounding islands as well.
Japan at this time was composed of many small factions, and nearly all of them had the goal of unifying Japan. For the Imagawa, it seemed possible, since they had such a massive force. But the brilliance of Oda Nobunaga's strategies lead to their defeat.
In this period, the samurai were held to be warrior nobility, and were the landholders of the land that the peasants worked. If a peasant offended a samurai, it was the samurai's legal right to kill him on the spot.
Bokken are a type of wooden katana that people would use to train their swordsmanship.
Men-yoroi are a type of samurai mask worn with the helmet. They're usually pretty frightening.
Hakama are a type of traditional Japanese trousers.
Tabi are a sock that has a parting, allowing the big toe to move freely. It's used with sandals and the like.
A dou is the main breastplate part of armour. It had pads that connect to it that protect the front and back of the upper thighs.
A kabuto is a typical samurai helmet.
Takamagahara is basically heaven in the Shinto religion.