Here's something you don't see every day: Japanese sailors unwinding by playing a naval-themed anime arcade game.

The chance encounter in the naval port town of Yokosuka was documented on Twitter by user T-Kum, in a tweet that went viral.

Image copyright Twitter: T-Kum

"I came here to play KanColle but it looks like the real sailors are already here," he wrote in a post that was retweeted more than 30,000 times.

A hugely popular web browser game available only in Japan, it is part of the Kantai Collection franchise which has spawned multiple manga novels as well as an animated television series.

But to fans and military history buffs, its appeal lies in the characters: anime schoolgirls named after actual naval warships.

'I found them in the ships games corner'

The Twitter user spoke to the BBC of his surprise as he walked into the arcade but also at how his post subsequently went viral.

"I took the photo in a games arcade in Yokosuka. I went in, as I often do, just to pass the time, and I found them in the ships games corner," he said, adding that he thought they must be sailors in training.

"It's not rare to see people in uniform in this town ... but I just thought it was a nice moment that they were sharing, spending what little free time they have relaxing like that, so I took the photo and posted it, making sure not to show their faces."

"I didn't expect such a huge reaction. My mobile alert was going off like crazy, and I didn't know what to do."

'The sign of a country at peace'

Twitter users reacted to his post expressing excitement, with many also noting this was a sign of a country at peace.

"Seeing this makes me relieved - There's no self defence force officer who wants to go to war," commented one Twitter user. "Without peace, they cannot read comics or play games."

It was a sentiment that struck a chord with the poster.

"It's only in peacetime that soldiers and trainees can spend their leave time playing games like this, so I suppose that's what people are reacting to," he told the BBC, but added that some Self Defence Force staff are involved in anti-pirate operations and do go on active duty around the world.

"As trainees, they can enjoy their time off. But once they become full-fledged officers and go abroad on operations, I hope they can still return home to relax and have fun. I hope Japan continues to be like that."

And on the question of the central irony of sailors playing sailing games: "I can only guess but I thought maybe it's because they like ships."

Reporting by the BBC's Yuko Kato and Heather Chen