Learning about cultural rules and etiquette — including dining etiquette — is essential when traveling to other countries. Most establishments in Japan, for example, have basic rules regarding how to properly eat sushi, and chef Jiro Ono, owner of famous sushi restaurant Sukiyabashi Jiro, has some advice to offer.
Sukiyabashi Jiro's website explains that it's acceptable to eat sushi with either your hands or chopsticks, but be careful not to let the rice crumble or spill any toppings. Potential diners are also warned that they shouldn't take photos of the food, let the sushi sit, or cut it in half, but one rule is even more dire than the ones already listed.
The website notes that the "greatest insult to the sushi chef" is to pull toppings off of the rice and eat the ingredients separately. Part of the art of making sushi is to combine flavors and ingredients perfectly, so taking the pieces apart is an insult to the chef's abilities; you can politely ask the chef to make smaller pieces for you, instead.