i found a good strategy. when the big boat comes for tea, *leave the total amount 5 teas short than what you need(important)* than wait till there is 10% left then buy 5 more teas! keep doing this and wait buy 30 tea and 30 opium(continously if you have a lot of money) when there is a decline in price. this is a gurantee win, trust me. LIKE SO THIS CAN STAY ALIVE