The 20-year-old, who played in last summer's U20 Women's World Cup, joins from Waseda University in Tokyo.

She becomes City's second signing in January, along with German defender Rebecca Knaak, and could be involved in their game against rivals Manchester United on Sunday.

"I'm aware how enormous this game is and if I'm given a chance I'd like to show my playing style," said Oyama.

"My dream is to play in the Champions League. I'd like to be able to contribute to the team as soon as I can.

"And as a young player, now that I'm in this team I want to play as many games as possible... seeing other young players [getting chances] inspires me to work hard like them."

City's women's director of football Therese Sjogran added: "Aemu is a very technically gifted player, there's a real buzz about her.

"She'll be exciting to watch this season and beyond, and there is real potential for her to become even better."