Merchants thronged to the large cities that were growing up around the castles at Edo ( population already 1 million in the 18th century ) , Osaka ( 400,000 ) , and Nagoya and Kanazawa ( each 100,000 ) all huge in comparison with European cities of the time .
Large cities like Edo , Osaka , and Nagoya and Kanazawa , which were huge in comparison with European cities of the time , brought to them many merchants ,