Place 4 large eggs in a saucepan and cover them with water. Bring to a boil, then cover and simmer for 10 minutes. Transfer to ice water for 5 minutes to cool.

Peel the cooled eggs under running water and mash them in a medium bowl until chunky.

Add Japanese mayonnaise, sugar, and salt to the mashed eggs. Blend until smooth and creamy.

Spread the egg mixture evenly on 2 slices of soft bread and place the other slices on top.

Cut the sandwich diagonally and serve on a plate. Enjoy cold or at room temperature.