On Friday, China’s Korean War epic “The Battle at Lake Changjin” became the highest-grossing film in the world for 2021, surpassing the Chinese New Year breakout comedy hit “Hi, Mom.”

The gritty war film co-directed by Chen Kaige, Tsui Hark and Dante Lam has grossed $845 million (RMB5.41 billion) in 29 days, marching past “Hi, Mom,” which earned $821 million at the beginning of the year over a 90-day period. Films are typically given a month-long release window in China, but they can be extended to a two-month run for successful titles. Decisions to allow an even longer run are rarer, and often due to political concerns or a dearth of other strong content.

“Lake Changjin” is currently China’s second highest-grossing film in history behind local title “Wolf Warrior 2″ ($854 million), which also features star Wu Jing and a jingoistic military theme.

The former has more or less dominated the China market since its Sept. 30 National Day release. On Friday, it was unseated from its top spot by the debut of James Bond film “No Time to Die,” which opened to $8 million.

Unlike its foreign competitors, however, “Lake Changjin” has been given a boost by measures such as local governments requiring cadres of employees to go on group outings to see the film in theaters as a patriotic education measure.

A sequel entitled “Water Gate Bridge” is already in the works. Stars Wu Jing, Jackson Yee and other main players will return to continue the story of the Chinese People’s Volunteer Army during a different maneuver of the same campaign at North Korea’s Lake Changjin, also known as the Chosin Reservoir, in the lead-up to the U.N. troops’ complete withdrawal from the North.

Specifically, it will center on a maneuver to blow up the Water Gate Bridge that was the only path of retreat for a U.S. troop division. According to Chinese state media reports, the Chinese forces had to bomb the bridge three times after the U.S. side rebuilt it after each attempt, succeeding at last only when soldiers strapped explosives to their bodies and embarked on a suicide attack.

Like its predecessor, “Water Gate Bridge” will also be co-produced by Bona Film Group and August First Film Studio, with Chen, Hark and Lam returning to co-direct. Lan Xiaolong and Huang Xin will remain on as screenwriters as well.

Reuniting the original team will be little trouble since most of the footage will actually be cut from material shot at the beginning of this year for “Lake Changjin” and re-edited to form the sequel, said Bona Film head and “Water Gate Bridge” producer Yu Dong. Some additional winter weather shoots will also take place in the coming months.

“This next battle will be even fiercer and the mission even more arduous,” he said. “The film will present all of this and let viewers see what…is the great spirit of the War to Resist U.S. Aggression and Aid Korea.” The latter term is China’s name for the Korean War.

Huang Jianxin, executive producer of both “Lake Changjin” and “Water Gate Bridge,” said, “The entire company made a huge sacrifice just to win a few seconds in which to bomb the bridge. These are the realities of war, and the film’s story is very touching.”