Director Moon Hyun-sung used the foundation of true events to tell the story of a team that united a divided nation for the first time in its painful history.

Summarily, the first-ever unified North-South team under the simple aegis "KOREA" was formed to compete in the 1991 World Table Tennis Championships in Chiba, Japan.

Six months later, in Busan, Jung-hwa is finishing her preparation for the 41st World Table Tennis Championships, to be held in Chiba, Japan; aside from caring for her father in the hospital, she is under huge local pressure to win a gold medal this time.

In Chiba, quarrels and fights break out between the two, mutually suspicious sides, exacerbated by young Northern hothead Choi Kyung-sub (Lee Jong-suk) and Southern joker Oh Doo-man (Oh Jung-se).

When political winds change again and just as suddenly an announcement is made to disband team Korea, the two young women must prove to their people and the world that teamwork can outshine the dark shadows of a painful history.

[3][4][5] When director Kim Jee-woon first came to her about the idea for a film about the 1991 championships, South Korean table tennis legend and Olympic gold medalist Hyun Jung-hwa reportedly answered, "Why didn't you approach me sooner?

Making his feature debut with As One, Moon said he felt it was crucial that his own voice as a director didn’t outshine the drama of the real-life story, so he let it unfold very naturally.

[12][17] Unlike Ha's direct training sessions with her real-life counterpart, Bae was unable to contact or meet with Ri Bun-hui, having to rely on videos and tutoring instead.

[13] The tournament games were shot at Andong University's indoor stadium, where a July heatwave was multiplied by the heat from lighting, raising the temperature to over 120 degrees Fahrenheit inside.

There were constant minor injuries from slips and falls, as well as from performing difficult moves, and physiotherapists had to be on standby on the set at all times.

Shooting the final game against the Chinese team was a culmination of the training and difficult photography, bringing all the players to genuine tears.

"[13][20] As One opened in South Korea on May 3, 2012, and despite competing against Hollywood films The Avengers and Dark Shadows, it was viewed by 1.2 million viewers 10 days after its release.