Sisu is a Finnish concept that combines inner strength, determination, perseverance in the face of adversity, and a strong work ethic. There is no direct English translation, but the concept can be somewhat expressed as "tough as nails" or "hard-bitten". To anthropologists, it is an appropriate invention for a cold northern land, fractured by thousands of lakes, and long under threat of being overwhelmed, militarily, linguistically and otherwise, by more powerful neighbours. Similar concepts exist among other cold-weather peoples, such as the Inuit and Chukchi.
Due to its cultural significance, Sisu is a common element of brand names in Finland. For example, there are both Sisu trucks and Sisu vitamins.
The term is commonly used in everyday speech to describe stoic toughness. For instance: Even after cutting his hand open and getting 12 stitches, he didn't shed a tear. Wow! He's got sisu! By analogy, the term has picked up new meanings. Depending on context, "sisu" can refer to spunk, attitude, self-confidence, etc.
SISU is also the acronym for the educational association of the National Sports Confederation for Sweden. The allusion is intentional.
