Over the years I've used many badminton rackets, with a wide variety of code numbering placed at the beginning of the shaft:
Can somebody give me detailed information about the meaning of those codes?
NOTE: There appears to be no universal, consistent standard for these codes as codes for a manufacturer/country may represent opposite meanings compared to another manufacturer/country.
G is in reference to grip sizes.
U is in reference to racket weight.
For a majority(1) of rackets:
In Japan, they range from G2, G3, G4 to G5 where G2 is the biggest size and G5 is the smallest size. In some countries, the opposite applies.