Samurai wear dou armor when going into battle. Anyone wearing a dou while not actively with a military unit will be challenged by the local samurai, therefore samurai tend to be unarmored most of the time. Samurai do wear jingasa and hachi gane without armor, and this is socially acceptable, but provides no in-game armor bonus.
A set of dou armor consists of the Dou (cuirass), Kote (gloves), Kabuto (helmet), and Suneate (boots). The Jingasa (armored coolie hat) and Hachi gane (headband with forehead armor) are sometimes worn in place of the Kabuto, especially by poor samurai. For battle, many samurai wear a Sashimono (back banner), with nobles wearing a Horo (cloak for nobles).
A set of dou armor provides 3 armor points. At the GM's discretion, he may allow a character wearing only one or two pieces of armor (often the jingasa) to provide one armor point.