Why does tojo say that it would be hard for japan to pull their troops out of china?

Here we are talking about Hideki Tojo was a prime minister and also the war minister of Japan and he lists several reasons why it would hard to pull the troops:

1. They sent  too many people there and it would be hard to bring them back. They have sent about one million troops over to China. It is really hard to transport that many people.

2. There were a lot of dead and wounded, about 100.000 people.