Bourdeto with octopus from Corfu

Boil the octopus in a pot with two cups of water and the vinegar for five minutes then take it out and cut it into pieces. 

Put the octopus back into the pot with the two kinds of pepper, the tomato paste and the oil and let it boil for two hours. 

Add the potatoes and let it boil for an additional half hour until the sauce thickens.