In addition, there is a theory that the TOKUGAWA shogunate distinguished between pre-Sekigahara tozama daimyo such as IKEDA, KURODA and HOSOKAWA clans who had maintained close relationship with TOKUGAWA clan well before, and post-Sekigahara tozama daimyo such as MORI, SHIMAZU and UESUGI clans who had submitted themselves to the TOKUGAWA clan's rule after the Battle of Sekigahara, so as to treat the two parties differently.
また、同じ外様大名でも比較的早い時期から徳川家と友好関係があった池田氏・黒田氏・細川氏などと関ヶ原の戦い後に臣従した毛利氏・島津氏・上杉氏などでは扱いが違ったとの説もある。