Remove the shells from the shrimp, leaving the last two segments near the tail. Wash thoroughly in salt water, remove the vein, rinse again, and pat dry with kitchen paper.

Cut the tail diagonally to remove excess water. Make four cuts halfway into the shrimp's belly and press the back firmly to straighten and flatten the shrimp.

Mix water and tempura flour in a bowl to create the batter. Coat the shrimp's body with the batter.