Time Out says
Turning the horrors-of-war psychodrama on its head---and, anatomically speaking, little else---Kji Wakamatsu's intimate chamber piece wages a gripping battle of the sexes. It begins with the waking nightmare of young bride Shigeko (Terajima, carrying the film) when her husband, Kyuzo (nishi), returns home to their rural village from the Second Sino-Japanese War battle zone. Actually, returns is too active a verb: The veteran is armless, legless, voiceless and, in Shigeko's tortured description, "nothing but a pile of flesh." Nonetheless, the mute is an honored "war god," with local deference and wifely duties due.
Soon come scenes of spoon-feeding and (unusually explicit for contemporary Japanese cinema) off-putting torso-on-top sex. But Caterpillar lurches into truly unusual territory when it's revealed that Kyuzo wasn't so great a husband, with a history of abusing and debasing. Quietly, Shigeko begins to assert herself in a careful campaign that's too tantalizing to spoil. (Stridently sad music and awkward flashbacks ruin the taut mood of gamesmanship.)
It's no surprise that Wakamatsu, nearing the 50th year of his career, came out of Japan's version of pornography---the "pink" film, frequently a site of thinly veiled feminism. Based on a banned short story from the 1920s, Caterpillar might be read as a reaction to hawkish nationalism, but it's more a cry for the unknown soldier in the kitchen and bedroom.