Mince the onion and soak in water, then pat dry with kitchen paper. Dice the zucchini and red bell pepper into 1cm cubes. Chop the boiled eggs finely.

Prepare the squid by carefully removing the innards and tentacles. Remove the cartilage, cut off the tentacles below the eyes, and clean thoroughly.

Heat sake in a frying pan until boiling, add the squid, cover, and cook over medium heat until the squid is fully cooked. Let cool and chop the tentacles.