Mokuzu Island

is an island used by travellers to resupply on stocks and weapons. The island has a shape of the moon, where the two sides almost form a closed circle. The water between the sides is calm.

The island is home to criminals, expecting travellers. They power various traps and mechanisms and wait for the mist to rise, whirlpools and rocks to emerge. They wait for the ship to sink, and then wait for the valuables to float so they could claim them.

Shikamaru and Tenten went there to buy the tools for the Fourth Shinobi World War, by storing them inside of Tenten's scrolls.

Trivia

 * The shape of this island is similar to Land of the Moon.