Diet was crucial to the shinobi as they had to work away from their homes for days, if not weeks, and they had to maintain physical and mental stability.
According to the Giyoshu military manual yonshaku-tenugui (four foot tenugui) could be used as a military ration when soaked in rice vinegar. Both the Giyoshu manual and the Shoninki shinobi manual state rice would be brought along to be fed to watchdogs that bark. This would quiet them.
Since shinobi were spies, their diet was tailored to their missions. A shinobi avoided eating anything that caused bad breath before their duties, like Chinese chives, leeks or garlic. Where shinobi lived, deer and wild boars lived and could be hunted and yet they never ate them because they believed that the meat of animals dulled their senses.
When an emergency occurred in which a shinobi’s food runs out, they had to eat from the wild which includes snakes, frogs, insects, weeds and even certain soils. Shinobi’s even feasted as much as possible and drank massive amounts of sake (酒) because it was important that they could deceive their enemies in a banquet. A shinobi was well trained to both handle going without food and handle excessive eating and drinking. Incidentally, in the age in which the shinobi flourished, tobacco got popular among people but shinobi avoided it because the smell of tobacco remains over a long period of time and causes bad breath.
Portable Rations Edit
Hunger pills were common among soldiers in Japan and they were usually formed into spheres. These are light and small but calorie packed. They are eaten to keep a person from starving.
Giyoshu Ration Edit
The Giyoshu manual has it's own ration recipe made from pine bark, ginseng, and white rice, which is mixed, powdered and formed into spheres. These spheres are then steamed. A person will not starve even if he only ate this ration for up to three days.
Hyourougan (兵糧丸) Edit
This was the basic type of shinobi's portable ration. The shape of a Hyourougan is spherical and about 10mm in diameter. Hyourougan is made from non-glutinous rice, fruits of the lotus, yams, fruits of the katsura, Coix, ginseng, and crystal sugar. The food tastes like cinnamon and herbs, and its texture is that of dumplings. A shinobi could be supplied with enough energy and nourishment by eating 30 Hyourougans a day.
Kikatsugan (飢渇丸) Edit
Kikatsugan is a dumpling about 40 mm in diameter. The function of Kikatsugan was similar to that of Hyourougan. Eating Kikatsugans gives a shinobi perfect preparation in terms of both his mind and body. Kikatsugan helps a shinobi especially when he is near starvation. Kikatsugan is made from ginseng, buckwheat, yam, dried chickweed, adlay, sticky rice and sake.
Suikatsugan (水渇丸) Edit
The intention of this food was to restrain the thirst of a shinobi. If a shinobi ate 3 Suikatsugans, he would be able to live 45 days without drinking water. Although this may be an exaggeration it is true that a Suikatsugan encourages the secretion of saliva so it is perhaps possible to go without drinking anything for about three days. A Suikatsugan is a pill about 9mm in diameter. It was made of licorice, Japanese mint, kudzu starch, dried plums, smoked plums, Poria cocos, kasyu and water.