Heat the takoyaki pan or takoyaki maker over medium to high heat.
Use a brush to generously oil its surface, including the space between the molds.
Once hot, pour the batter to fill the holes to around 75%.
Add 1 octopus piece (or 2 if they're small) to each hole.
Now sprinkle the other fillings: katsuobushi powder, tenkasu, green onion, beni shoga.
Once the balls harden enough to be turned without ripping, turn each one to the side and fill the gap with more batter.
Keep turning, stuffing in the sides (and if need be, filling up with more batter) until the balls have a nice are perfectly round and browned.