Moon Phases in Japanese - Vocabulary

There are many anime which talk about the "Moon phases," or gessou 月相, for a reason or another. Like the full Moon, for example. Or the full Moon. The full Moon. And... the full Moon. And also, of course, the red, blood Moon. Anyway, this time I'll talk about these and the other lesser moon phases nobody ever cares about.

To begin with, the word for "Moon" is Japanese is tsuki 月. That's the same kanji as used for the word "month" in Japanese, gatsu 月, but one has a kun'yomi reading and the other has an on'yomi reading.

The "Moon phases," gessou 月相, are:

• New Moon
  shingetsu 親月
• Waxing crescent Moon
  jougengetsu 上弦月
  or jougen 上弦
• Full Moon
  mangetsu 満月
• Waning crescent Moon
  kagentsu 下弦月
  or kagen 下弦

Source: japanesewithanime.com (CC BY-SA 4.0)

For the waning and waxing Moons, the word gengetsu 弦月 can be used for either. Since the first quarter and the third quarter are also called "half Moon," you can use he word hangetsu 半月 to talk about. The han 半 there means literally "half."

Another thing about these two phases is that jou 上 and ka 下 are written with the kanji for "up" and "down" respectively. So a jougengetsu 上弦月 is a half-Moon, gengetsu 弦月, that is raising, increasing, while a kagengetsu 下弦月 is lowering, decreasing.

The shin 新 in shingetsu 新月 means "new," like in the adjective "new," atarashii 新しい. On the other side, the man 満 in mangetsu 満月 means "full" and is found in words like "satisfied," manzoku 満足.