Lemon Somen is a cold somen noodle dish topped with sliced lemon and salted green onions. Somen is a summertime staple in Japan where it gets so unbearably hot and humid. The only thing you can eat in the middle of hot days can be cold somen noodles. It is quick and easy to prepare, so you don’t need to stand in the kitchen for too long, either. No wonder somen is one of the most commonly eaten lunch at home during the summer in Japan.