What is this? Japan Jersey from 1984

[commando]

Hello Vintage Enthusiasts,

I'm a sucker for jerseys from the 1980s, so I picked this up... But what is it? Perhaps a baseball or soccer jersey? It was manufactured by Descente and has their tag in the inside tail. Interestingly, the factory tagging includes the uniform number "9" and the year "84," something I don't recall seeing from Descente before.

Everything is sewn on, to include the letters, numbers and Japanese flag.

If you happen to know what this is, I'd love to know! Many thanks -- Anthony