Combine the soy sauce, water, sugar in a small saucepan. Cook over medium-low heat, stirring frequently, until slightly thickened. Remove from the heat and let cool.

Mix the rice vinegar, sugar, and salt until dissolved. Pour over the warm rice and gently fold until evenly seasoned. Let the rice cool to room temperature.

Pat the shrimp dry with paper towels. Make four shallow cuts along the belly side of each shrimp. Turn them over and gently press to straighten them.

Lightly dust the shrimp with flour. Whisk together the egg and water, then add the cake flour and mix lightly. A few lumps are fine.

Heat about 1 inch of oil in a frying pan. Dip the shrimp in the batter and fry until crisp and light golden brown. Transfer to a rack or paper towels and let cool.

Trim both ends of the cucumber and cut it lengthwise into quarters. Remove the seeded center and cut into long strips.

Cover both sides of a bamboo sushi mat with plastic wrap. Cut the nori sheet in half crosswise. Place one half on the mat and spread sushi rice evenly over the surface with wet hands. Flip the nori over so the rice side faces down.

Place the cucumber and shrimp tempura about 1/3 inch from the edge closest to you. Using both middle fingers, hold the filling in place. With your thumbs and index fingers, lift the edge of the bamboo mat and the roll together, bringing the edge of the nori just beyond the filling.

Once the roll lands, firmly press it several times to shape it. Squeeze from the center outward, then from the outside back toward the center, making sure the filling is secure and the roll holds together.

Next, use your right hand to pull the bamboo mat slightly forward while your left hand supports and rolls the sushi. When the roll lands again, repeat the same shaping motion, pressing firmly from the center outward and from the outside inward.

Repeat this rolling and shaping process one more time to create a tight, compact roll that won’t fall apart when sliced. For exactly what I do, please watch the video.

Thinly slice the avocado lengthwise. Fan the slices out and place them across the top of the roll. Cover with the bamboo mat and gently shape the avocado around the roll.

Wet your knife before each cut and slice the roll into 8 pieces. Top with unagi sauce, spicy mayo, tobiko, and black sesame seeds before serving.