I made a Japanese character Calendar cube with English ruby (agate).
I think to make a Japanese character's Calendar cube, but it can be used only Japanese.
Then I consult with Carter about English ruby (agate) because I don't know detail of date representation.
Thank you for your great help, Carter.
The 'ruby' means written above kanji to show how to pronounce in Japan. 'ruby' means 5.5 pt printing size in GB, and it's called 'agate' in U.S.A.
(It's a little trivia.

)
When arranged it by English, it represents with Japanese KANJI.
But there is a problems. In Japanese, '-teenth' was written to '13-19', then the 'thir - nine' ruby was needed to write to center's '1', but center pieces are only 6. The '3th - 9th' is in the last resort.
This variation is my and Carter's first idea.
Perhaps, there are some other idea.