there might be a misunderstanding concerning "work visa".
there is no actual visa called work visa in japan, however there r plenty of visas that allow u to work, some in a very limited sector, some with broader definitions. most visas and especially the most common ones held by ppl from developed or industrialised countries require a university degree*, however not the entertainment or artist visa.
MOFA: A Guide to Japanese Visas - Types and Categories of Visa
*this is in no way a fact, but a mere feeling that i have.