Despite the a priori desiratum of assimilating the derivation and interpretation of wh-questions in Japanese to that in English, empirical evidence shows that overt displacement of wh-phrases in Japanese is not the same as overt wh-movement in English.
the examples in (6) clearly show that a non-wh-phrase object may be scrambled across the subject to a position other than SpecCP: (6) a. Dare-ga sakana-o tabeta no?