In Japan, the dan (段) and kyu (級) rank systems are commonly used in Go and martial arts. The kyu rank system usually starts from the lowest rank at 10 kyu, and goes up to 1 kyu, the highest rank, while the dan rank system starts at 1st dan and usually goes up to no more than 10th dan. (Some martial arts organizations reserve lower kyu, such as 7-10, for children, and/or have an age limit, i.e 16, before they can be awarded dan.) Both rank systems are usually combined, so that 1st dan is the next rank above 1 kyu. In martial arts, 1st dan usually corresponds to a 1st degree black belt, with each dan rank above that corresponding to a higher black belt degree.
This system is no longer confined to just Go and martial arts, as it has become quite popular as a way to rank players in various games, especially in Japan. Of course, this is also subject to Rank Inflation.
Often used in video games as a method of Gameplay Grading.
- Kenichi: The Mightiest Disciple:
- Sakaki Shio, the karate master, refers to himself as 100th dan in brawling. Nobody's willing to challenge it.
- In a later episode he faces a swordsman opponent who claims to be an 8th dan in swordsmanship and who tells Sakaki that to defend from an armed opponent a bare handed martial artist must have three times the dan grade of the armed opponent.
- In many Ranma ½ Fan Fics, Ranma is able to determine a person's martial arts rank simply by observing their body language and how they walk.
- 3-gatsu no Lion is a manga about a teenager in professional shogi. As such, whenever the story focuses on that particular aspect of his life, the terms are mentioned every now and then, usually when introducing a new player.
- Go is the Ur-Example.
- In an inversion of Rank Inflation, Go ranks start around 30-27 kyu, but most martial arts and video games start at 10 or 9 kyu.
- The reason for this is that in Go, your rank is based on the handicap you need to play an equal game against a first-dan player (which naturally reduces as you get stronger). As the standard for reaching the first dan rank is set by competition with recognized dan players, the standard for dan has gone up with time. So new players need higher and higher handicaps to beat the established masters. Result: more kyu ranks.
- Shōgi also employs both the dan and kyu ranking systems. Amateur players in-training to become professionals through the Shoreikai system are ranked from 6 kyu to 3 dan. Kishi (i.e. professional players) rank from 4 dan to 9 dan.
- beatmania IIDX has the Dan'inintei (rank certification) mode, which has ranks from 7 kyu up through 10th dan, then finally Kaiden. Each rank has a set of four songs that is significantly harder than the songs for the rank immediately below them, and to qualify for a rank, a player has to clear all four songs in a row, on a single albeit somewhat-easier-than-normal life bar.
- The first two Tetris: The Grand Master games have grading systems that closely resemble kyu and dan ranks, with grades going from 9 to 1 (the kyu part), then S1 through S9 (the dan part). The first TGM game has the titular "Grand Master" rank after S9, while TGM2 adds the M grade between S9 and GM. TGM3's grades bear less resemblance to kyu and dan ranks, since it has, after S9, m1 through m9, followed by Master, Master K, Master V, Master O, and Master M, and of course, GM.
- Many Mahjong video games will rank players on a kyu and dan system. Most start players at 10th kyu and increase their rank when they win matches, or decrease their rank if they lose. The Japanese Professional Mahjong League also uses a dan ranking system for professional players, though a dan rank in the professional league is obviously much harder to obtain than the same dan rank in a game.
- Mahjong Fight Club has 10 kyu through 8th dan, followed by Master and Kouryuu Lv. 1 through Kouryuu Lv. 99.
- MJ has 10 kyu through 10th dan, then many ranks after 10th dan.
- Toupaiou has 10 kyu through 9th dan, then Meijin (Master), Ryuuou (Dragon King), and finally the titular Toupaiou rank.
- Tenhou starts players at Shinjin ("Newcomer"), promotes players to 9 kyu after their first win, then ranks continue up to 10th dan, followed by the final Tenhou Rank.
- Virtua Fighter 2 introduced these rankings to the series.
- Tekken games starting with 5 also uses kyu and dan ranks. However, if you want one in the arcade version, you need a card for the game.
- In the Japanese version of Magical Drop III, Puzzle mode gives you a rank upon game over. The American and European versions remove this.
- Money Idol/Puzzle Exchanger, show you a certificate with your rank on it after playing. Likewise, only in the original Japanese version.
- In Sonic Adventure 2 Battle, the "chao" pet system allows for karate matches, with your chao's rank being depicted with kyu and dan.
- In Mabinogi, skills begin at rank F and go up to A, where they continue to 9 through 1. Once a skill is rank 1, you can begin earning Dans by completing Advancement Exams.
- In Aion, Abyss rank is a 9 kyu and 9 dan ranking system, where kyu ranks are called "Soldiers" and dan ranks are "Army Officers". Kyu ranks are gained by earning Abyss points, and lost by spending Abyss points to purchase equipments, consumables, or greater stigma skills. Dan ranks instead require GP (Glory Points / Honor Points), and such ranks are restricted to the top 1,000 players with the most GP per faction on each server. Players holding 5th dan or higher (100 spots per faction per server) can transform into powerful Guardian Generals.
- In Fate/stay night, it's mentioned that Fujimura Taiga is a five-dan in kendo.