The tension between creating and claiming value

In a negotiation, I believe that the tension between creating value and claiming value comes about because when you create new value and then divide that value between the two parties, you have to give up some of the value that you might have received had you simply stuck to a competitive strategy.  When you attempt to create value, you have to take a more cooperative approach and therefore you do have to reveal some of your information that in a more competitive approach you'd keep closer to your vest. Once that information is revealed, you expose yourself to losing some of your value.  

However, if good will is what you seek, then creating value is a better strategy.  First off, it is a good strategy because the person you are negotiating with will consider the deal to be more fair.  Secondly, both parties should end up receiving a fair share of the newly created value.  And finally, in a strictly competitive negotiation, one party ends with a much larger portion of the pie (or even the whole thing), and so there is a chance that you would end up being the loser if you stick to the competitive style of negotiation. When you create value, you should both end up as winners.