Kisenosato Yutaka said he had been struggling with injuries but had wanted to continue wrestling to repay fans for their support.

In 2017, he became the first Japan-born wrestler in almost two decades to reach the rank of grand champion, known in Japanese as "yokozuna".

The only two wrestlers left at the elite level are both from Mongolia.

"I feel that I did everything I could," a tearful Kisenosato told reporters at a news conference.

"I was supported by so many people... I have nothing but gratitude."

He will be adopting the name of Araiso as a sumo elder. It is expected that he will train younger wrestlers as a coach in his retirement.

Who is Kisenosato Yutaka?
Kisenosato, whose real name is Yutaka Hagiwara, is from Ibaraki, north of Tokyo.

As a child, Kisenosato was a pitcher in his school's baseball club before he chose to train as a wrestler at a stable in Tokyo.

The 32-year old made his professional debut in 2002 and reached Japan's top Makuuchi division in 2004 at the age of 18.

After being runner-up on multiple occasions, he finally clinched his first tournament victory - and thereby his promotion to yokozuna - in January 2017.

Kisenosato went on to win his first tournament as a yokozuna in March that year.

However a chest muscle injury kept him out of eight straight tournaments in a row, the longest career pause of any yokozuna in sumo history.

Since competing again in September 2018, Kisenosato has posted eight successive losses, the worst run of any grand champion since the competition format was introduced in 1949.

"I was gradually recovering, but I was unable to wrestle in my own style," said Kisenosato, the first Japanese-born yokozuna to retire in 16 years.

Only two active yokozuna now remain in professional sumo wrestling: Mongolian-born pair Hakuho Sho and Kakuryu Rikisaburo.

In recent years, sumo has been hit by falling numbers of Japanese recruits, partly because it is seen as a tough, highly-regimented life.

The last Japanese-born wrestlers to reach the top were brothers Takanohana and Wakanohana, who made it to yokozuna in 1994 and 1998 respectively.