Daf Yomi - Sukkah 2 - A Little Bit Shady

A Sukkah is designed to provide shade. The Mishnah states that if the sunny area of a Sukkah is greater than its shaded area, the Sukkah is invalid. Rashi explains that the minority of shaded area on the Sukkah floor is negated by the majority of sunny area. The commentators wonder why it was necessary for Rashi to offer this reason. Is it not obvious that a Sukkah that does not have the necessary amount of shade is invalid? Why does Rashi have to mention that the minority of shaded area is negated? The Eimek Bracha cites Tosfos here to answer this question. The Gemara states that there are those that maintain that if a Sukkah is higher than twenty amos, but is wider that four square amos, the Sukkah will be valid. Tosfos explains that the Chachamim have established that even if a Sukkah is more than a thousand amos high, if it is wider than four squared amos, there still will be some shade coming from the s’chach into the Sukkah. It is evident from the words of Tosfos that for a Sukkah to be valid, it is required that the Sukkah should provide at least minimal shade. A Sukkah that has a minority of shaded area would be valid if not for the fact that it is negated by the majority of sunny area. Regarding a Sukkah that has a minority of valid shade and there is a majority of shade which is invalid, i.e. when the shaded area is due to the height of the walls, then the Sukkah is valid. The reason for this is because there is a principle that shade cannot negate shade.