According to the recently-published report,
Japan Handset Vendor Marketshare by Operator: Q3 2016, around 8 out of 10 handsets shipped by Softbank in Japan in Q3 2016 turned out Apple iPhones, mostly iPhone 6S, SE and 7 devices.
iPhone 6S and SE devices drove up the volume through this Japanese operator in July and August of 2016 while the newly-launched
iPhone 7 device helped to accelerate the sales in September 2016.
The in-detail handset market share by vendor by operator in Japan on a quarterly basis can be viewed
at this link, published by Handset Country Share Tracker (HCST) service.