Distributor Toho opened the Studio Ghibli film on 481 screens, the widest ever releasefor a local film, for a $30,867 (Y3.28m) per screen average over the three days.
In comparison to Miyazaki's all-time Japan box office champion Spirited Away ($285.8m, Y30.4bn), released on the same three-day holiday weekend in 2001, Ponyo earned 96.6%. Average ticket price was slightly higher at the time ($11.52 in 2001 vs. $11.43 in 2008).
On Sunday, distributor Toho projected Ponyo's final earnings based on admissions up until Saturday afternoon. Using the opening weekend admissions of Spirited Away as comparison, Toho pegged Ponyo's final take at approximately $244.4m (Y26bn), 83% of the 2001 film's $285.8m (Y30.4bn) haul.
Such calculations have become more commonplace in the media but don't factor in competing releases or other circumstances and therefore rarely come to fruition, as successes such as Ghibli's own Tales From Earthsea and Fuji TV's Hero have shown.
Ponyo battled for a similar demographic against the latest Pokemon film, Pikachu The Movie 2008, which claimed the second spot in the top ten, with Toho estimating a Y5bn ($47.1m) payday for the second year running. In 2001, the annual Pokemon film opened two weeks before Spirited Away.
While Ponyo is sure to surpass 2006's Tales From Earthsea (directed by Miyazaki's son Goro), whether it will catch the second biggest hit in Japanese history, Miyazaki's own Howl's Moving Castle ($185.6m, Y19.6b), is not guaranteed.
Like North America, Japan is becoming more about opening weekend shock and awe. However, Miyazaki films have longer, steadier runs than any other type of release. Spirited Away took over one year to amass its take.
Ponyo is already booked for a 20-week engagement at the 656-seat Hibiya Scalaza, where Miyazaki and his cast greeted audiences on opening day.