Japanese “vacancy” button emoji 🈳 is part of the Symbols and Alphanumeric Symbols emojis. On some systems it can be accessed by using :japanese_vacancy_button:, :ja_vacancy: or :u7a7a: shortcodes.
It was approved as part of Unicode in 2010 so it should be displayed properly on all devices.
Tags: Ideograph, Japanese, Japanese “vacancy” button, “vacancy” and 空