Tojo is a slur used to describe Japanese in a derogatory way. General Hideki Tojo, Japanese Prime Minister during WW2. Ordered the attack on Pearl Harbor.
The word Tojo is a racial slur that has been used historically to degrade and dehumanize japanese. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to japanese. If you are unsure about whether or not it is appropriate to use the word Tojo, it is best to err on the side of caution and avoid using it in any situation.