Meteocentrale website forecast shows that radiation fall-out will reach Japan western region on Wednesday afternoon (on Honshu island : cities of Osaka, Kyoto, etc. down to Hiroshima and Yamaguchi – as well as Shikoku island) as can be seen on the screenshot below. This is the first time since the creation of SurvivalJapan that we report air-borne radiation in western Honshu and Shikoku. Since this blog is fairly new, it can be assumed that radiation fall-out over this area happened in the past and it is consistent with citizen groups radiation monitoring, which detect levels low yet superior to normal background natural radiation (Cf. CRMS Civil Radioactivity Monitoring Stations in Kansai Area Today in SurvivalJapan).
Wind streams are sucked in from Fukushima by typhoon no. 15 which is leaving Okinawa and heading north as can be seen on the following screenshot. Therefore this should be an exceptional situation but it dispels any absolute safety certainty about the rest of Honshu. Until further information, I deem only Kyushu and Okinawa archipelago to be nuclear-free territories from today.
Besides, the renewal of short-lived Iodine-131 has been interpreted as a renewed criticallity in Fukushima, although of course officially denied (Cf. Fukushima in Recriticality ? in SurvivalJapan) – hence fall-out may include more than just the usual Cesium.