What is a "Da'Har Master"? The title was first used by John Colicos's Klingon character, "Kor". Although an exact description is not given, it is implied that Kor holds this title for his past strategic and military efforts. A defining factor was his victory over the Romulans in Year of Kahless 2270 in the "Battle of Klach D'Kel Brakt". The most notable aspect is that a "Da'Har Master" is highly respected throughout the Empire.
In a recent game release called "Klingon Honor Guard", it is insinuated that the term "Da'Har Master" is the leader of a school of a fighting style much like the Terran martial arts. In the game, the player is a new recruit of the Honor Guard and must investigate the attempted assassination attempt of Chancellor Gowron. The player fights his way from mission to mission; he begins to reveal the plot and the conspirators behind it. At the end, he must fight the treacherous leader of the Honor Guard, after discovering his heinous involvement. After defeating the leader, the player character is bestowed the title of "Da'Har Master" by Chancellor Gowron. By these descriptions, it is a title that is earned for great deeds of valor and honor and bestowed by the Chancellor of the Empire.
Klingon fandom has a tendency to generate it's own concepts in areas that are not clearly defined. There are many ideas about this title and even though each one is different, that does not mean they are wrong.
Almost all Klingons are skilled in most hand and energy weapons. But the need for high skill in these leads to the concept of a "Da'Har Master". They would be so proficient in handling and use of weapons that they could perform realistic combat without actually inflicting damage. Thus some "Da'Har Masters" could come from the theatrical community, while other could be military trainers. After all, the average Klingon could tell the difference between a rehearsed fight and one that is conducted by pure skill.
Another is actually considered by one who studies and has adapted terran forms of martial arts to develop the Klingon fighting form known as "Mok'bara". By these descriptions, the title is earned for mastery of weapons or unarmed combat.
It is also consider that a "Da'Har Master" is someone who has earned the respect of his peers and has made major contributions to Klingon fandom as a whole. These individuals are not skilled fighters, or strategists but someone who continues to keep alive the concepts that most members of Klingon fandom find the most appealing. Loyalty, Duty and most of all Honor are the main traits that draw many individuals to the ranks of being a Klingon.
This is seen not only by those who dress as Klingons, but those who write about Klingons or depict Klingons in art or strive to follow those concepts in their personal lives. Being Klingon is a mindset, and a feeling of the heart. It is from this that those worthy and respected earn the title of "Da'Har Master".
No matter which description is chosen, a "Da'Har Master" is revered for their efforts, skills and accomplishments and has no authority over other Klingons except by the respect they have and continue to earn in the eyes of fellow members of Klingon fandom.