Dynasty Warriors 7

To unlock this achievement, you have to found every weapons of a single type, for example the axes or the swords.
There are ten weapons by each type. You can find by three differents ways.
Fisrt, by buying them from the Weapon Dealer or the Merchant. You can find the firts in the story mode before some battles and in the conquest mode in every cities. the Merchant appears by 2 to 5 battles and sometimes proposes weapons.
Secondly, when you defeat officers, they leave behind them their weapons if you dont have this one.
Third, you can find special weapons only when you complete The "Treasure battle" in the Conquest Mode. In the same mode, you have also some battles (the ones with the sword) who the reward is a random weapon, a one that you dont possess.
Finally, the tenth weapon can only be purchased if your character had the Smithing skill (for example Zhuge Liang or Guo Huai).