Israelism/Yahwism is Biblical Monotheism, because there is no 'Trinity God' in the entire Bible.
Israelism is Yahwism without using the divine name in the belief. Yah-wism uses the divine name YaHWeH (Hebrew).
Yahweh, is the English transliterated name of the Almighty given to Abraham, Isaac, Jacob/Israel and to Moses, Exodus 3:15-16.