Final answer:
The Tokugawa rulers forced out the missionaries who were trying to convert the Japanese people to Christianity because they believed it posed a threat to their authority.
Step-by-step explanation:
The Tokugawa rulers forced out the missionaries who had been trying to convert the Japanese people to Christianity because they believed that Christianity posed a threat to their authority. By eliminating the missionaries, the Tokugawa rulers sought to maintain control over the converted daimyo who did not fully support the shogunate. They also feared that adopting the foreign faith would give disloyal daimyos opportunities to conspire against them.