・ 音 オン
Sino-Vietnamese: ân
Cause 因 over heart 心: keeping in your heart the one who made you what you are, hence gratitude and kindness.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
恩師に手紙を書いた。 (おんしにてがみをかいた)
I wrote a letter to my former teacher.