The Day of Honor, known in Klingon as Batlh jaj, was a time of celebration and ritual for the Klingon people. It is customary to serve Rokeg blood pie during this time.
This Klingon holiday is a time when the warrior must reflect on their life and judge whether the actions they have taken are honorable or not. The warrior must also respect the honor of both friends and enemies which essentially means everyone, regardless of race, are treated as Klingons. This allows anyone to participate in Suv'batleth. (VOYepisode: "Day of Honor")
It is said that a Klingon warrior must make an alliance with a hated enemy during the trial. (DS9comic: "Day of Honor")