Did you know our weekdays are based on Roman or Gallic/Germanic gods ?
This means that if you know the weekdays in Japanese, Latin, French, Italian, Spanish, … or any other latin-based language, you will have no problem remembering some of the planet names in Japanese!
Unfortunately the link to these planets is lost in the English language (except for Saturn, Sunday and Monday)
Monday: Moon 月
Tuesday: Mars 火星
Wednesday: Mercury 水生
Thursday: Jupiter 木星
Friday: Venus 金星
Saturday: Saturn 土星
Sunday: the Sun 日
I just remember Mercury is a liquid at room temperature so it’s 水星, Venus is the brightest object in the sky (after the sun and the moon) so it’s shiny 金星, Mars is the red planet so it’s 火星, Jupiter is patterned like woodgrain so it’s 木星, and Saturn matches Saturday so it’s 土星.
After that, the last three are Uranus the king of the Sky (天王星), Neptune the king of the Sea (海王星) and Pluto the king of the Underword (冥王星).