Tanaka began collecting in 2000 after seeing an exhibition of contemporary artists. After hearing that "no one purchases contemporary artwork", he began purchasing in hopes of being a modest support to the artist and came to collect works of unknown Japanese artists in particular. Thanks to a career turning-point in 2014, he has begun to rethink his collection style. In addition to young Jaopanese artists, he seeks those emulating historical Japanese painting styles and emerging artists from abroad.