Shrimp and Cream Sushi Triangles

Name: Shrimp and Cream Sushi Triangles
Ingredients: 400 grams Sushi rice; 500 milliliters Water; 1 piece Kombu seaweed (approximately 8 x 8 cm); 5 tablespoons Rice vinegar; 2 teaspoons Salt; 2 teaspoons Sugar; 4 dried Shiitake mushrooms; 3 tablespoons Soy sauce; 3 tablespoons Sake; 2 tablespoons Horseradish cream; 1 tablespoon Cream cheese; 1 tablespoon Beet juice; 1 piece thin Cucumber (about 10 cm); 1 piece pickled daikon radish (about 10 cm); 6 peeled, cooked Shrimp; ½ ripe Avocado; 1 teaspoon Lemon juice; 2 roasted Nori seaweed; 200 grams cooked Sushi rice