The gi (pronounced "gee," with a hard-g) is a standard uniform worn in many martial arts schools, consisting of baggy pants and a double-breasted jacket. Both are designed to be generic, so that techniques that involve grabbing the uniform will work on both European and Asian clothing.
A gi is typically made from rugged canvas, since many grabs and throws can stretch or rip normal clothes. Additionally, when everyone looks the same, students must reach into themselves to find what makes them different a unique, and cultivate that instead of hiding behind pieces of flair.
Calling a martial arts uniform a gi is mostly an English-language thing. In Japanese, “-gi” is a suffix. The more appropriate term would be a keikogi (“practice uniform”) or dōgi (“Way-uniform”).
The pants (zubon) are held up with a drawstring. (Contrary to popular belief, karate belts play no role in keeping your pants up.) Gi pants feature a large rhomboidal patch in their inseams (a “diamond crotch”), to allow the student to stretch and kick without ripping their pants.
The gi jacket (uwagi) is double-breasted, and held closed with a belt. Karategi often have string ties at the sides to help keep the jacket closed, but they are often more trouble then they are worth. Small items can be stored in the little pocket formed by the belt and the left front side. The gi jacket has a reinforced collar and lapel, since these are the most commonly-grabbed parts, and are subject to the most abuse. Since karate involves less grabbing and grappling than jūdō and jūjutsu, karategi are usually lighter and not quilted like jūdōgi.
The belt (obi) is made from quilted canvas, and is extremely long, because it must wrap around the waist twice, before being tied with a square knot. When tied properly, both ends of the belt hang downward. Belts are color-coded to the student’s rank, as a mnemonic to help instructors know where the students are within the school's curriculum.
Each manufacturer has their own gi sizing system, which does not correlate to any other sizing system. You need to try before you buy. Most instructors have extra gi sitting around, so this isn’t an issue, but if you insist on getting your own from a website or catalog, check their return policy, or caveat emptor.
Gi sleeves and pant legs arrive extremely long, since manufacturers error on the side of caution and assume everyone to be gangly. You will most likely need to hem the sleeves and pants. A properly fitted gi meets the following criteria:
- The sleeve cuffs must be above the wrist, but below the elbow.
- The leg cuffs must be above the ankle, but below the knee.
- The jacket must cover the butt.
- The ends of the belt must hang down to the bottom of the jacket.
Women may have some difficulty finding a properly fitting gi, because they are unisex clothes -- and by unisex, we mean men’s. As such, gis do not have darts (the triangular patches which account for bust sizes), and they assume the wearer's hips and waist are of equal size. Women should also note that the left side of the jacket goes over the right.
Please comply with the following additional rules and regulations:
- Once you have been issued a gi, you are not permitted to train without one.
- Always heave a clean gi before training.
- No one (except children waiting for their ride) should wear their gi in public.
- Never wear a gi without an obi, and never wear an obi without a gi jacket.
- Male students should consider a groin cup and supporter to be a part of their karate uniform.
- While they may seem uncomfortable at first, it beats the alternative.
- Female students are permitted to wear T-shirts, camisoles, or rashguards under their gi jackets to preserve their modesty.
- Long hair should be tied back into a ponytail or bun.
- Students must train barefoot to preclude rolling their ankles. Wearing shoes can also contaminate the mats with staph/MRSA or ringworm. If a student has a foot-related medical issue that requires wearing shoes, they should discuss this with their instructor, so that an acceptable shoe type can be agreed upon.
- Finger and toe nails must be kept trimmed. Long nails will cut other students. You cannot make a proper fist with long nails, which will cause broken hands.
- For student and item safety, the following are forbidden during training:
- Hats and sunglasses
- Necklaces, bracelets, watches, and rings (except for wedding bands).
- Any and all forms of body piercings must be removed prior to training. Tape or bandages will not secure piercings; we’ve got some horror stories.
- Chewing gum and/or food.
- Metal or plastic items worn in the hair.
Traditionally, karateka had no standard uniform. Since many jūdō and jūjutsu moves involve grabbing the opponent’s clothes, most of the great karate masters throughout history fought in their underpants.
When Gitchin Funakoshi came from Okinawa to pitch karate to the Japanese, it was originally rejected, in part, because karateka lacked uniforms, which the Japanese saw as being necessary for spiritual development. Funakoshi copied the karategi after the jūdōgi, because jūdō was extremely popular at the time, and could not be rejected.