It was the Foxes striker that got things started for the Samurai Blue.
He peeled off the last man to find himself onside and alone in the box, before directing a header beyond Bozhidar Mitrev in the Bulgaria goal.
It was his 48th goal for Japan in his 101st cap for his nation. It follows an excellent debut season with Leicester, with whom he scored six goals but was a regular as they won the Premier League title.
He was not however the only Premier League scorer on show. In fact, a Southampton defender ended up outdoing him.
Maya Yoshida scored twice for Japan in the game. He nodded a header into an empty net to make the score 4-0 and did so again, this time with his feet, to make it 5-0.
It was the Southampton player’s ninth goal for his country – but remarkably his fifth for Japan this season.
A brace from former Manchester United star Shinji Kagawa as well as goals from Takashi Usami and Takuma Asano made it seven for Japan – whilst Mihail Aleksandrov and Ivaylo Chochev scored Bulgaria’s consolations.
It takes Japan’s winning streak to five games with the Leicester and Southampton stars pivotal to their success.