The yam is the very object that can give a man political and economic power, however it is the one thing he can not grow for himself. This fact is the basis for the way the Trobriander culture functions. To understand the importance f the yam in the Trobriander culture, one must understand who grows and distributes the yams. It all starts with the preparation f the land. Due to the poor soil in the area, the Trobrianders use 'slash and burn' or 'swidden' cultivation to enrich the soil with minerals. Although married couples work together to prepare the yam fields, growing yams is primarily the man's job. The man uses young people to help him in his yam garden. He will later pay them with yams he receives. They may use this to buy things from the trading store or to buy secrets about the land and how it came into possession by the owners. Although it is the man that labors rigorously to grow the yams, they are never really his to use. The yams are grown for a single woman, usually his sister; therefore the garden is named after her. Although the yams are grown for a mans sister, it is her husband that will use the yams for political maneuvering. The yams, after staying on display at the gardens for about a month, are taken directly to the woman's husband's yam house. The only one that can use the yams while they are still at the garden is the gardens namesake, and this is only under a dire emergency such as a death in the family. The amount f yams a man gives to his sister is a direct, and publicly viewed, reflection f the relationship between the woman's husband and the grower.
An abundance f yams can be given if the grower sees his brother-in-law as a hard worker, or good provider for his sister. This exchange is beneficial to the man giving the yams to a hard working man because he has repayment f woman's wealth coming back to him.
The grower may also give an abundance f yams to a woman whose husband is seen as a political force to be allied with. It is the obligation f the receiver f the yams to return the generosity for the gift f yams by giving him cooked yams, taro, and pieces f pork if available. The distribution f the yams is designed to encourage good social relationships between neighbors and family. It is also highly dependent on hard work. No one will wish to give yams to a man that has nothing to give back in return because he is lazy.
Having a yam house is a good indication f someone with political prowess. A man can not build his own yam house. The yam house can only be built by a man's in-laws, and this will only happen after the man proves his worthiness through years f hard work. A yam house is like a summer house in that it is possessed only by well established men. A man is bound to his wife's family because he depends on them to give him yams and also to build his yam house when he is ready for it. Weinder writes, 'A man can develop political power only if he has strong support from his wife's relatives, and this support is primarily demonstrated through yam production' (92). The woman's family is also reliant on her husband for yams in the event f death in the family. Therefore, there is a working relationship that requires an equal effort on both sides to be productive.
Yams should be viewed more as a currency with symbolic value that can be used as a food. The main purpose f the yam is