SIM card options for iPhone 5/6 (Tokyo)

Hi all,

I'm sitting here at the airport about to fly to Tokyo and am trying to research options for SIM cards for 6-months. It appears the options are limited, so just wanted to see if anyone has dealt with this and what you have found to be effective. Alternatively, if anyone has a pay-as-you go plan set up and is leaving soon that I could take over, that would work as well.

Welcome your thoughts/suggestions.

Thanks,
Ryan