The term 'Da and Ja' is a reference to the two main characters in the popular manga series 'Death Note'. Da is the protagonist, Light Yagami, and Ja is the antagonist, L Lawliet. The crossword solution for this term is 'YESES', which refers to the fact that both characters are highly intelligent and often come to the same conclusions. They both have a strong sense of justice and are willing to do whatever it takes to achieve their goals.