Found in the grounds of Fukuoka Women’s University. This moth is not a good flier and is therefore presumably poisonous (if eaten by birds I mean), hence the bright colors. I couldn’t find a common name for this species, but its Japanese name is hiroobi-tombo-edashaku. A related and very similar-looking species (Cystidia couaggaria) is a pest of apples and other fruit trees – the caterpillars are referred to as plum cankerworms.
Lepidoptera: Geometridae (shakuga): Ennominae (edashaku)
Cystidia truncangulata = hiroobi-tombo-edashaku.