What is this symbol? (assumed compliance mark like CE / FCC)
I was wondering this myself, however some fairly extensive image digging revealed that it’s something approximate to the Japanese equivalent of the FCC certification mark, sometimes called Giteki. Japanese law seems to prescribe that radio devices should have this mark to be used in Japan.

http://incompliancemag.com/article/wireless-certification-in-the-land-of-the-rising-sun/