Geng som, literally "sour curry", gets its sourness from tamarind juice. Usually it has fish or seafood cooked in it. Geng som can seem more like a soup than a curry, but initially a curry paste is made to use as a base for the dish.
Very yummy, I only used 1tsp of red curry paste due to small children and they loved it. We didn't have bamboo shoots. We added a bit of lemon grass as well. - 13 Sep 2013 (Review from Allrecipes AU | NZ)