Thousand Cranes by Yasunari Kawabata.

Kikuji Mitani is on his way to a tea ceremony that will be performed at the inner cottage of Engakuji Temple in Kamakura, Japan. When Kikuji received an invitation to this ceremony from Kurimoto Chikako, his deceased father’s former mistress, he initially thought it was being conducted in memory of his deceased father, but a postscript mentioned that she wanted him to meet Yuriko Inamura, her student. As he again reads the note, Kikuji remembers that, when he was taken by his father to visit Chikako, he accidentally viewed the large birthmark that covers half of her left breast. Kikuji has been haunted by this image since then.