From the IJF website
The first national symbol stuff we replace with club name.
3. Judo uniform (judogi)The contestants shall wear a Judogi complying with the following conditions:
a)Strongly made of cotton or similar material (see guideline) , in good condition (without rent or tear). The material must not be so thick or hard or slippery as to prevent the opponent from taking a grip.b) Blue for the first contestant and white or off-white for the second contestant. (See Appendix).
c) Acceptable markings:
1)National Olympic abbreviation (on back of jacket). Size of the letters 11 cm.
2) National Emblem (on left breast of jacket). Maximum size 100cm2.
3) Manufacturer's trade mark (on bottom-front of jacket, on bottom front of left leg of the trousers and on one end of the belt). Maximum size 20 cm2.
It is permitted to place the manufacturer's trade mark on one of the sleeves but inside the 25cm x 5cm area instead of at the bottom front of the jacket. The IJF Official suppliers are allowed to place the IJF Logo above their trade mark (in direct contact).
4) Shoulder markings (from collar - across shoulder down the arm - both sides of jacket). Maximum length 25cm and maximum width 5cm. (The same advertising or national colours on both sides)
5)Advertising on the sleeves, 10 cm x 10 cm on each sleeve (different advertising allowed). These 100 cm² have to be fixed just below and in contact with the stripes of 25 cm x 5 cm.
6) Indication of the placing (1st, 2nd, 3rd) at the Olympic Games or World Championships, in an area of 6cm x 10cm at the bottom front left side of the jacket.
7)The contestant's name may be worn on the belt, lower front of the jacket and upper front of the trousers up to a maximum of 3 cm x 10 cm. Also the contestant's name or abbreviation may be placed (printed or embroidered), on the back of the jacket above the National Olympic abbreviation, but in no case in a position to prevent an opponent from grasping the back of the jacket. The letters can be up to a maximum of 7cm high and the length of the name can be up to a maximum of 30cm long. This 7cm x 30cm rectangular area must be located 3cm below the collar of the jacket and the back identification must be fixed at 4cm below this area. Note: For IJF Events and the Olympic Games, the names are indicated on the 30 cm x 40 cm Bibs.
8)The contestants must bring judogi without any back identification at the sewing desk.