Based on the rule here, it says "5 or more" ... I am in a game right now that the opponent has a chance to place 6 in a row ... but he/she hasn't do it yet ...
(hide) Tired of placing boats or Espionage pieces at the begining of the game? You can go to Game Editors and save some of your favourite positions for future use. (pauloaguia) (show all tips)