Kyu

The amazing thing is that he actually found three people who are worse than him.

A weeaboo term used for students or amateurs of Go. You start out at 30 Kyu (or 30k) and work your way down to 20kyu, 10kyu and then 1kyu. After that your rank is called "Dan" and you start at 1dan and work your way up. Dan rankings go as high as 7dan. If a 7dan player decides to pursue a career as a professional Go player from there, they can upgrade their 7dan rank to a 1 "professional" dan rank, abbreviated 1p. Professional rankings continue from there, with the worlds strongest players having the coveted 9p ranking.

You can walk into any tournament and claim to be any kyu rank -- there's no way to measure it, people don't care much because only pikers and weekend-warriors would brag about it. If you claim to be 30kyu and kick someone's ass who claims to be 1kyu, one of you is obviously lying. Most organizations won't let you claim dan rank without proving yourself first. Since nobody can agree on what a "dan" rank is worth then you could be 5th dan at your local club but sweating it out at the kyu tables when you play in a state tournament.

There's no shame in being kyu rank when playing Go. One of the more awesome things about the game is how well and how easy it is to handicap the better player. 3rd dan players will sit and play a game for fun with 20 kyu players and it doesn't have to be boring for either of them.

Kyu and Dan are also used in Riichi Mahjong, but the system is slightly different. Players start out without a ranking and have to earn their kyu rank, but start out at 9kyu instead of 30kyu. Saying "I think I'm about 9kyu" in Go means "I think I'm a halfway decent player, but I'm not great or anything." Saying the same thing in Mahjong has the effect of "I'm so fucking bad at this game I could play with my asscheeks and there wouldn't be a noticeable difference."

"Kyu" and "Dan" are also used in martial arts schools. Kyu levels are the coloured belts; Dan levels are the black belts.