We report on two experiments that ask when and under what linguistic conditions comprehenders construct detailed shape representations of mentioned objects, and whether these can change over the course of a sentence when new information contradicts earlier expectations. We used Japanese because the verb-final word order of Japanese presented a revealing test case where information about objects can radically change with a subsequent verb. The results show that language understanders consistently generate a distinct and detailed shape for an object by integrating the semantic contributions of different sentential elements. These results first confirm that the tendency to generate specific shape information about objects that are involved in described events is not limited to English, but is also present in Japanese, a typologically and genetically distinct language. But more importantly, they shed light on the processing mechanism of object representation, showing that mental representations are initiated sentence medially, and are rapidly revised if followed by a verb that implies a change to an object shape. This work contributes to ongoing research on incremental language processing – comprehenders appear to construct extremely detailed semantic representations early in a sentence, and modify them as needed.