How many countries serve Sushi?

It's impossible to give an exact number of countries that serve sushi. Here's why:

* Sushi is a global phenomenon: Sushi has become incredibly popular worldwide, with restaurants serving it on every continent. Even in countries where it's not a traditional cuisine, you'll find sushi restaurants and grocery stores selling sushi ingredients.

* Definition of "serving sushi" is subjective: Does a country "serve sushi" if they have one small sushi restaurant? Or do they need to have a thriving sushi scene?

* Cultural nuances: Sushi is often adapted to local tastes, making it hard to define what constitutes "true sushi".

However, we can say that sushi is enjoyed in a vast majority of countries around the world. Its popularity is a testament to its deliciousness and adaptability.