It's always been the case that singular Android devices typically don't get iDevice numbers (although Samsung is changing that). Android has overtaken iOS globally largely because of its breadth of devices. Thus, news of a single device overtake the iPad is huge.
A survey of 2,400 consumer electronics stores in Japan showed that Google's Nexus 7 tablet (built for it by Asus) had 44.4 percent of the market vs. the iPad's 40.1 percent. The survey was performed by market research firm BCN in December.
Price is a big draw for the Nexus 7, according to Nikkei, which published the survey. The Nexus 7 is about $100 less in Japan than Apple's least expensive tablet, the similarly sized, though slightly larger, iPad mini.
There is a caveat to the results, though. The survey noted that there was a shortage of the iPad mini and that this may have contributed to Apple's lower market share.
3.6 million tablets were sold in Japan in 2012. According to figures from IDC Japan, this is expected to rise to 4.9 million units this year.