Finely slice the scallion. Combine water, Hon-Tsuyu, and pepper in a saucepan and bring to a boil. Reduce to low heat and simmer.
Boil J-Basket frozen ramen in a separate pot according to package directions. Drain the ramen.
For one serving: In a large bowl, add the sesame oil, approx. half of the soup, and 1 serving of ramen noodles (in this order). Top with ½ of the Tenkasu, scallions, and Sakura shrimp. (Some soup may be left over depending on the size of the serving bowl).