Watermelon radish, or koushin daikon [芯大根], is a type of hitherto relatively unknown vegetable that has become increasingly popular in Japan since the early 2010s.
Traditionally, radish or daikon [大根] is a stable ingredient that often appears in miso soup and oden etc. The word “daikon” itsself is (justly or unjustly) associated with drabness, dorkiness and frumpishness.
Inquiry - Koushin Daikon