12th anniversary of one's death
Buddhist memorial service held on the 12th anniversary of a person's death, counting the year of death as the first anniversary.
Next month is the 12th anniversary of my grandmother's death.
First anniversary of death; 十三回忌 is the 12th anniversary.
Second anniversary of death; 十三回忌 is much later in the memorial cycle.
32nd anniversary of death
Compound of 十三 (thirteen) + 回忌 (anniversary of death). The number thirteen reflects the traditional Japanese counting where the year of death is the first anniversary, making the 12th solar year the 13th memorial year.