The kanji 月 (tsuki, 'moon' or 'month') in a box. It stands for a monthly amount, such as a monthly fee or rent.
In Japanese contexts 🈷️ can mark monthly prices or plans. Outside Japan some people use it for the moon or for 'month', but it is rare. Anyone who reads kanji knows the character at a glance.
Facts
Japanese “monthly amount” button 🈷️ is an emoji in the symbols category, under alphanum. It is one of the early emoji from Japanese phones, standardized in Unicode 6.0 (2010). On GitHub, Slack and other apps you can type it as :u6708: or :japanese_monthly_amount_button:. People also look for it with words like “Japanese”, “amount”, “button”, or “ideograph”.
Timeline
2010Added to the emoji standard (Unicode 6.0)
Design history
Google (Noto)
2015
2017
2019
2021
Twemoji (X, Discord)
2014
Google Noto Emoji images: Apache 2.0. Twemoji graphics by X Corp and contributors: CC-BY 4.0.