Hey there Luis. Of course you can travel to Japan, although it depends on how long you mean to Travel? Most countries can spend up to 90 days in Japan upon arrival without 'applying' for a Visa, as in it is given to you upon arrival as a tourist visa/pass.

If you meant for longer term stay than that then you would need to apply for a Visa, even if you're half-japanese.

I am not entirely sure of the whole procedure with Visa's for those who hold Japanese lineage. But I would recommend going onto the Japanese Ministry of Foreign Affairs website (MOFA) and having a look at the Visa's section. I would also recommend ringing up the Japanese consultate for more information about your query