These was a pretty good article distributed by Kyodo News Agency which gave a quick history and run down of the big sports drinks in Japan. Of course there are many, many sports drinks in Japan and more are introduced every year, but I think this article was right to narrow it down to 3 high profile sports drinks which interesting histories.
Coca Cola - Aquarius This was introduced in the 1980s and is an isotonic drink. It remains a strong brand for Coca Cola here in Japan, but is not used outside Japan for some reason. Outside Japan, Coca Cola sells Poweraide.
Meiji Dairies Corporation - VAAM This was the first amino acid drink introduced in Japan (or possibly anywhere) and it is based on the amino acid mixture which hornets feed on and which allows them to fly long distances. Naoko Takahashi won the Sydney Olympics Women's Marathon while using VAAM.
Otsuka Seiyaku - Amino Value This is another amino acid drink, but it stresses the value of branched-chain amino acids, which are said to assist recovery. Mizuki Noguchi won the Athens Olympics Women's Marathon while using this Amino Value.
It is interesting to note that Gatoraide has tried several times to crack the Japanese market, but has failed with several different partners.