This article explores the history and cultural significance of the number 731 in Japan. It has been used for centuries, with its earliest known usage dating back to the Edo period (1603-1868). Today, it is seen as a symbol of luck and prosperity and is commonly found on storefronts, clothing items, lottery tickets, and other forms of gambling. It is also associated with Emperor Meiji whose reign saw great advances made by Japan both domestically and internationally during his lifetime. Common misconceptions about 731 are also addressed in this article.