In Indian mathematics, 0 (zero) is called Shunya. When translated, it becomes empty. The color of the Heart Sutra (Hannyashingyo) means "there is no substance (sky) when all things (colors) are essentially scrutinized." In the mystical thought Kabbalah, Ein is translated as Emptiness and is represented by 0. Also, the shape of the letter 0 (zero) comes from the Sanskrit word 0 (Shunya "०"). In other words, 0 (zero), Shunya, sky (ku), and Ein mean "Emptiness" in the same meaning.