Line an 8¾in x 3¼in (22½cm x 8cm) loaf pan with aluminum foil. Cut two pieces of cardboard the width and height of the loaf pan to act as separators. Wrap cardboard separators with aluminum foil and place them equally spaced in the pan.

Place strawberries, sugar, and water in a small saucepan over medium heat. Mash strawberries with spatula and cook till thick and syrupy, about 8 minutes. Strain mixture, pressing with spatula to extract the juice. Discard pulp.

Stir cocoa powder with 1 tablespoon hot water in a small bowl till well combined. In another small bowl, combine honey with 1 tablespoon hot water.

Preheat oven to 325°F (165°C).

Place egg whites in mixing bowl and beat at high speed (speed 10*) for 30 seconds until slightly foamy. Add sugar in 2 to 3 increments until firm peaks form, about 4 minutes.

Add yolks one at a time at medium low speed (speed 4*) until well combined, about 1 minute. Add sifted bread flour and beat until just combined. Add mirin and continue to beat for another minute.

Pour batter through a sieve into a large bowl. Press with a spatula to help batter go through sieve.

Divide batter equally into 3 portions of 4½ oz (130g) each into 3 separate bowls. Add strawberry sauce (about 3 tablespoons) and 2 drops of red food coloring to one of the bowls and gently stir with a spatula till well combined. Repeat with cocoa mixture and honey mixture.

Pour each of the flavored batter into each section of the prepared loaf pan. Tap pan on the counter to remove air bubbles. Pull out both cardboard separators and immediately place into preheated oven.

Bake for 45 minutes or until top is evenly browned. Toothpick inserted into cake should come out clean.

Remove pan from oven and drop it from a one foot height onto the counter to prevent shrinkage. Place a piece of parchment paper on a large piece of shrink wrap. When cake is cool enough to handle, lift cake up by holding the edge of aluminum foil. Turn cake upside down onto parchment paper. Peel off aluminum foil. Wrap shrink wrap over cake and leave overnight in the refrigerator (right side up) to preserve moisture in the cake and for flavor to develop. Alternatively, warm cake can put into a Ziploc bag with the foil and left in the refrigerator (right side up) overnight.

To serve, cut off edges on all sides except the top and bottom with a very sharp knife. Then cut into thick slices using a sawing motion.