But given the fact that his activities were very unnatural as a legitimate child of the dominant feudal lord on the Tokugawa side even though he was disowned by his father and he entered into Fukuyama later, there is speculation that he played a role in spying on daimyos on theToyotomi side in Western Japan.
しかし、勘当されたとはいえ徳川方有力大名の嫡子としては非常に不自然な行動をしている事や、その後の福山への入封などから、西国の豊臣方大名の動向を探るための家康の密偵的な役割もあったのではないかとの推測もある。