Banzai is a Japanese term that is used to express joy or celebration. It is often shouted when someone achieves something great, such as winning a competition. In the context of a crossword puzzle, the term Banzai can be solved by the answers SURFER (6 letters) and OAHU (4 letters). Oahu is an island in Hawaii, and is known for its surfing culture. Therefore, SURFER is an appropriate answer for the clue Banzai.