In animation, realism means not deciding for the viewer how to feel
Most Western theories of animation assume the medium's strength is what live action can't do: flight, transformation, impossibility. Takahata's counter-argument is that animation can also do what live action does poorly — the precise calibration of a particular kind of light, the grain of a memory, the weight of ordinary things.
He spent a full production day on a watermelon-cutting scene in Only Yesterday, instructing animators on the correct knife angle. This is the discipline of attention that Mizoguchi or Naruse would have recognized in live action — transposed to a medium where every frame is a deliberate decision.
Takahata's realism isn't about looking real. It's about leaving the viewer free. A photograph of a watermelon being cut leaves the viewer to respond however they respond. An animated watermelon, drawn by an artist with a strong hand, can be made to enforce a feeling. Takahata's discipline was to draw it so the viewer remained free. This connects directly to his "free spectator" theory: realism in animation is not a goal of imitation but a means of withholding authorial pressure.
The discipline is counterintuitive: painstaking attention to realistic detail is less manipulative than stylized exaggeration, because it doesn't tell you how to feel. Accurate observation leaves a gap for the viewer. A strong expressive line fills it.
Source claim: Takahata argued that realism in animation is a discipline of attention that preserves the viewer's freedom to respond, not a goal of imitation.