Sales in Japan (July). Source: Electronista

The iPhone, which has had a tough time competing in the Japanese market, finally broke through in July with the launch of the iPhone 3GS.

According to a report in Electronista, market data from Gfk Japan shows the 32 GB iPhone in the No. 1 spot for July, ahead of Japanese-made phones from Sharp, Panasonic PC , NEC, Casio and Sony Ericsson (a Japanese/Swedish joint venture).

The 16 GB model came in at No. 9, ahead of the Sharp SH001.

An earlier report from the market research company BCN showing the two iPhone models occupying the No. 1 and No. 2 spots for the week of June 22 to 28 was discounted because that was the week Apple AAPL launched the 3GS in Japan. (See here.)

That the 32 GB iPhone ended the month of July in first place is harder to dismiss as a transient, opening day phenomenon.