Where can you but superdry jackets?

Not in Japan. They are a British company.

SuperDry tries to deceive people into thinking their products are Japanese. You will frequently see Japanese characters and the Word Japan next to their logo. But in reality the company is British, and the products designed there. The goods are almost entirely manufactured in China.

The Japanese characters they print next to their logo have poor grammar, it has been taken from a dictionary translation. They don't even have one Japanese person to translate basic phrases for them on a logo they print repeatedly on all their products.