For the VOY episode of the same name, please see "Day of Honor".
For the novel series, please see Star Trek: Day of Honor.
The Day of Honor was a Klingon holiday. On this day, a warrior evaluated his or her deeds for the past year to see whether he had been honorable. It was customary to serve Rokeg blood pie on this day.
The traditional ceremony on the Day of Honor included eating the heart of a sanctified targ, drinking mot'lach from the Grail of Kahless, enduring the ritual of twenty painstiks, engaging in battle with a bat'leth master, and traversing the sulfur lagoons of Gorath.
In 2374, B'Elanna Torres and Tom Paris designed a holo-program for the Day of Honor. However, Torres quit shortly after it began. (VOY: "Day of Honor")
In the non-canon comic book "Day of Honor", it is mentioned that on the Day of Honor a Klingon warrior must make an alliance with a hated enemy in order to defeat their common foe.