This possible error fare deal with Alitalia is available in travel period till 30th of June 2015.Max stay in Brazil 1 month. All these European cities are easy to reach either by bus or low cost airlines. To check your connection possibilities from your home town directly you may check through Skyscanner. Cheap accommodation in Japan is possible to compare and book here.
Booking samples
Germany - Japan from €377
UK - Brazil from £292
Brussels/Amsterdam - Japan from €391
Travel dates to Brazil is easiest via Ebookers here using +- 3 days searching too.
Booking sample of cheap return flights from Europe to South Korea for €377 here. In this case you would be flying from Berlin to Tokyo on 3rd of June and returning from Asia back to Europe on 16th of June 2015