" With posture, it is important to keep your face neither tilted up nor down, nor leaning to one side, nor grimacing. Your eyes should be composed and your forehead free of furrows. Wrinkles should be confined to the area between your brows. Your eyes should not roll nor blink and your eyelids should be narrowed slightly, taking in a broad view of the surroundings. The line of your head and nose should be straight, with the chin protruding slightly. The neck is upright with the nape tensed, shoulders lowered, back straight, backside in, and with the feeling that your whole body from the shoulders down is a solid entity. Push down from the back of your knees to the tips of your toes and thrust your abdomen slightly forward so that your lower back does not stoop. "
― Miyamoto Musashi , Complete Musashi: The Book of Five Rings and Other Works: The Definitive Translations of the Complete Writings of Miyamoto Musashi--JapanÆs Greatest Samurai