U.S. films beat Chinese films in Chinese box office sales in a landslide, with the five highest-grossing films during the June 20 weekend coming out of Hollywood. "Godzilla," "Maleficent," "Edge of Tomorrow," "X-Men: Days of Future Past" and "Grace of Monaco" all beat Chinese domestic films in ticket sales. "Transformers: Age of Extinction," which hit China on Friday (the same day as in the U.S.), is likely to extend this trend.

"Transformers: Age of Extinction" is the fourth installment of the Michael Bay blockbuster franchise. While the film is a continuation of the series, it represents a beginning in another sense: Hollywood and Chinese film executives are closely following "Transformers'" box office performance as a test of how large the Chinese movie-going market really is.

The movie grossed an estimated $3.5 million in China alone during its debut, a record in that country, with global earnings totaling $8.75 million from evening showings. Industry experts speculate that "Transformers" could be the big hit of the summer and break box office records, especially in China.

This result has top Chinese film officials worrying about domestic movies getting lost beneath behemoths like Optimus Prime and Godzilla. China Film Bureau chief Zhang Hongsen likened these releases to a war being waged in theaters.

"This is the year when the battle between Hollywood and China really begins," Zhang said during a forum at a recent gathering of the State Administration of Press, Publication, Radio, Film and Television (SAPPRFT). "Chinese films are encountering serious challenges, and 2014 is a crucial year to decide who the winner will be."

Zhang and other Chinese moviemakers are concerned that their territory is being taken over and that domestic studios and distributors will not be able to compete.

"The main point is that we need to defend and fight for our cultural territory. On the economic aspect, we will have to see if we will be forced to surrender," Zhang said.

However, Chinese laws regulate the number of foreign films imported each year, which provides some relief for domestic filmmakers concerned about ticket sales: Until 2017, when the agreement with the World Trade Organization expires, only 34 internationally made movies can be seen in Chinese theaters.

In 2013, ticket sales in China totaled a whopping $3.9 billion. Hollywood companies are jumping at the opportunity to get a portion of this market, as U.S. ticket sales are declining and DVD sales dropping even faster. "Transformers" may help Hollywood pocket a large chuck of summer box office sales.

"With the release of 'Transformers 4: Age of Extinction,' domestic film's market share will fall below 50 percent," Zhang said.

From Hong Kong to Hollywood, stakeholders are laying claim to a large market that seems to be headed for a foreign invasion, at least when eating popcorn.