Prepare the Sakura Tare. Combine ingredients in a pot and let sit for 15 minutes to meld. Heat over low heat, stirring occasionally. Once simmering, boil for 30 seconds. (This is the secret! This versatile sauce is great for rice bowls and stir-fries, so make extra for convenience.)

Prepare the dashi broth for the soba dipping sauce. Add 600ml water and 2 dashi packs to a pot and let it sit to draw out the kombu's umami.

Make the tempura batter for the shrimp. In a bowl, add 2 tbsp mayonnaise and gradually add water in 3 additions, mixing to emulsify. Switch to chopsticks and gradually add 50g all-purpose flour. Dissolve the flour by submerging it in the water, being careful not to overmix. The batter should be cold, so keep it in the refrigerator until just before frying. (This is the secret! Gradually adding water to the mayonnaise and mixing to emulsify prevents separation. Don't overmix the flour; letting it dissolve by submerging it is key to achieving crispy, light tempura.)

Prepare dusting flour. Place all-purpose flour for dusting in a separate tray.

Prepare the shrimp. Peel the shrimp, then make a diagonal cut at the tip of the tail to drain water. Break the sharp tip of the tail. Make a cut along the back and remove the deveiner. Turn the shrimp over and make cuts about one-third of the way through its body at 4 places. Press firmly from the top and sides to extend the shrimp, cutting through the muscle fibers. (This is the secret! Cutting the belly and pressing firmly from the top and sides to break the fibers ensures the shrimp fries straight.)

Season the shrimp and coat with dusting flour. Sprinkle salt (a pinch to 1/4 tsp) on the shrimp. Generously coat with the dusting flour, shaking off any excess. Arrange the shrimp on the tray with their tails spread out.

Prepare to fry the shrimp. Heat frying oil in a pot to 160°C (320°F). Prepare a tray and rack for lifting out the fried shrimp. At the same time, bring a large pot of water to a boil for cooking the soba noodles.

Fry the shrimp. Remove the batter from the refrigerator. Once the oil reaches 160°C (320°F), lightly dip the shrimp in the batter, avoiding coating the tails, and carefully lower them into the oil. Fry 2 shrimp at a time, depending on the size of your pot, for 2 minutes. If you want to create a 'flower' effect on the tempura, drop small amounts of batter onto the shrimp's belly with chopsticks while frying. After about 1 minute, gently flip them. Once golden brown, drain well on the rack. (This is the secret! Do not coat the tails. After placing the shrimp in the oil, use chopsticks to drop batter onto the shrimp's belly for a decorative effect. Try not to disturb them too much while frying.)

Finish the soba dipping sauce. Gently heat the dashi broth prepared with water and dashi packs for about 10 minutes. After 10 minutes, remove the dashi packs without squeezing them, letting any excess liquid drip off. Add 6 tbsp Sakura Tare to this dashi. Start with 4 tbsp if you prefer a lighter flavor and adjust as needed. Bring back to a boil just before serving.

Cook and rinse the soba noodles. Add the soba noodles to the boiling water and cook for 1.5 minutes less than the package instructions (e.g., if it says 4.5 minutes, cook for 3 minutes). Drain the noodles quickly in a colander and rinse thoroughly under cold running water to remove excess starch. (This is the secret! Cooking for 1.5 minutes less and rinsing under cold water helps retain the noodles' chewiness and prevents the dipping sauce from becoming cloudy.)

Prepare warm soba and dipping sauce. Keep the water used for cooking the soba on very low heat to maintain warmth. Bring the soba dipping sauce to a rolling boil. Taste the warm dipping sauce; it should be slightly on the stronger side so it's perfect when the noodles are added. Once the dipping sauce is boiling, add the rinsed soba noodles and warm them for 30 seconds. Drain the warmed soba noodles again in a colander. (This is the secret! Reheating the soba noodles prevents them from cooling down too quickly once placed in the serving bowl, ensuring a warm dish.)

Assemble the dish. Place the warmed and drained soba noodles in a serving bowl. Pour plenty of hot dipping sauce over the noodles. Top generously with chopped scallions. Serve with the freshly fried shrimp tempura. Enjoy!