Some people might mistakenly believe that tuna is called tekka, but there is a clear difference between the two. For example, Tekka Don and Maguro Don are both donburi dishes made with tuna, but Tekka Don mainly uses the red part of the tuna known as "akami." Maguro Don, on the other hand, is not limited to red meat, and other parts of the tuna, such as toro, are sometimes used. In conclusion, the word "tekka" is only used to describe the red meat of tuna.