The commencement of human dissections in Japan during the Edo period is often depicted as the individual achievement of Yamawaki Tōyō. In 1754, this renowned scholar of the "School of Ancient Prescriptions, " feeling unable to resolve discrepancies in the Chinese classical literature, succeeded in obtaining permission for a dissection and was allocated a corpse at the execution place in Kyoto. However, a closer look at this issue reveals that the paradigm change to gaining knowledge through anatomical studies did not occur suddenly after centuries of stagnation. Beginning with the arrival of western medicine in the mid-17th century, this paper demonstrates how foreign and indigenous medical, social, political and religious stimuli gradually led to a new attitude toward human dissections and a rising awareness of the merits of anatomical observations. Decades before Yamawaki counted the number of human viscera, an ophthalmologist had discovered the faculty of the eye as a means for new insights and bone-setters had begun to revise textual knowledge by observing and manipulating the skeletons of rotting corpses. Yamawaki’s accomplishment does not lie in the nature of his dissection or the (quickly outdated) results, but in the sheer fact that he carried out the dissection with the permission of the shogunal authorities and managed to publish his findings. Furthermore, among those physicians who quickly followed his example, we find Kawaguchi Shinnin, whose intellectual and mental breakthrough has not been recognized sufficiently yet. In Kawaguchi’s case, there was no searching through the classical literature, no detached reflection and no awe resulting from the knife and the body fluids. The dissection that he conducted in 1770 was an unemotional "clinical" search for new insights by measuring sizes, determining positions, colors and consistencies, and by manipulating and investigating. The paper finishes with a comparison of the basic traits of anatomical illustrations in Japan and Europe.