The Japanese cellular market appears to be on the brink of significant change, but not in the way that many observers had expected when e-commerce giant Rakuten first launched into the mobile business. Rather than Japan’s incumbents being up-ended as India’s were by Reliance Jio or France’s by Free Mobile, it is likely that the big three – NTT Docomo, KDDI and Softbank – will remain firmly in charge. Reports abound that KDDI is poised to acquire Rakuten Mobile, while NTT Docomo is edging ahead of the challenger in developing an Open RAN platform that it can market to operators round the world. When Rakuten launched its mobile operator in 2020, there was speculation that the Japanese operators – technically…