1. Clean the konbu by wiping it lightly with a cloth.
2. Cut the konbu into 2-centimeter-wide partial strips against the grain, but don't cut all the way to the edge -- see illustration.
3. Add the water and konbu to a pot, and cook uncovered over a slow fire.
4. Just before the water starts to boil, remove the konbu from the pot. The liquid should be a light yellowish or greenish color.
5. Add shaved katsuobushi to the water as it starts to boil.
6. After the liquid has been boiling a minute or two, turn off the heat.
7. Quickly remove the shaved katsuobushi from the liquid with a filter or strainer or cloth. Try to remove the katsuobushi while it's still floating on the surface, before it has a chance to sink.
8. Allow the liquid to cool, then add the liquid, flour and eggs to a bowl and mix.
Make a small test batch of 4 or 5 takoyaki at first, to check the consistency of the batter. Add more flour or water as needed.
1. Oil the takoyaki pan.
2. Add pieces of chopped octopus to each cup.
3. Pour in the batter.
4. Add benishoga, negi and tenkasu to taste.
5. Cook the takoyaki pieces until they achieve the desired degree of firmness, turning them over frequently.
6. Remove from the pan and serve with sauce and/or mayonnaise.