Brazilian Jiu-Jitsu Belt, Kosen

Brazilian jiu-jitsu belt KOSEN, available from white to black. Tightly woven cotton, a reinforced rank bar, gold embroidery on the visible end. A belt built to survive several years of training, not to look good on promotion day.

Meets IBJJF rules

The IBJJF rulebook is specific about belts. Width between 4 and 5 cm, a black rank bar up to brown belt, red or white for black belts, and enough length that each end hangs 20 to 30 cm once the knot is tied.

The KOSEN meets all three. Just pick the right length: it is the one criterion on which a uniform check can turn away an otherwise perfectly legal belt.

Getting the length right

A belt that is too short comes undone on the first guard pass. One that is too long drags on the mat and gets in the way. The rule is simple: after two wraps and the knot, 20 to 30 cm should remain on each side.

Sizes run from A1 to A5 based on waist measurement, not on your gi size. A lean athlete in an A3 gi may well wear an A2 belt. Use the chart below, it gives the actual lengths.

The embroidery

The gold section is written in katakana: ファイター reads faitā, the Japanese transcription of the English word fighter. It is not decorative calligraphy picked at random, it is a readable word, written in the syllabary Japanese reserves for foreign terms.

Should you wash your belt?

Tradition says no, that a belt absorbs its owner’s experience and that washing it would erase the work behind it. It is a good story, and it is a recent one, spread largely by social media.

Reality is simpler. A belt spends every session in contact with your gi, the mats and your training partners. It collects exactly the same bacteria and fungi as the rest of your kit. Jiu-jitsu skin infections, ringworm and impetigo first among them, make no exception for folklore.

Wash it. At 30 °C, with your gi, no fabric softener, line dry. A black belt will lose a little depth over the years, a white belt will stay white, and nobody on the mat will hold it against you.

One belt per rank, or one for life?

Every promotion calls for a new belt. Plenty of people keep the old ones. It is the only object in this sport that tells the story of a progression. If you are starting out, buy a white one and do not get ahead of yourself: rank is awarded, not purchased.

FAQ

Is the rank bar stitched or glued?

Stitched, along its full height. That is the area that takes the degree stripes, so it has to survive repeated pulling and needles.

Does the belt shrink in the wash?

Slightly, like any cotton, and mostly on the first wash. Allow for that: between two lengths, take the longer one.

Can I use it at IBJJF events?

Yes, subject to the length check described above, and provided the colour matches your rank.

Does it work for judo or karate?

Physically yes, but ranking conventions differ between arts. This belt is made for Brazilian jiu-jitsu and its rank bar follows BJJ conventions.