The Reds have agreed a deal to sign the 23-year-old midfielder from Borussia Dortmund, subject to him passing a medical and obtaining a UK work permit.
Until then, Kagawa is focused on his international duties and Japan’s upcoming World Cup qualifiers, against Jordan on Friday and Australia on 12 June.
"I am yet to sign the contract," he told Soccer King. "For now, I need to focus on the final qualifiers so we can get good results against Jordan and Australia."
Arsenal’s Ryo Miyaichi, who was on loan at Bolton last season, is excited by his friend and Japan team-mate’s imminent move to Old Trafford.
"It would be great if us Japanese players could bring excitement to the Premier League together. I want to follow his lead. By learning what he is good at, such as playing in small spaces, I would like to become a better player."
Japan captain Hasebe Makoto added: "When I was a child, Japanese players only moved to big clubs in cartoons. It would be nice if more Japanese kids wanted to be like Shinji."