Sa Murra is an ancient game, trace of it has been found in an egyptian tomb dated 700 BC, it was also played in greek age and even by the romans, who called it Micatio ( from micare digitis "signing with fingers").
The game spread then in all Italy and in Sardinia, especially in those territories with a strong rural tradition; There's indeed speculation that this oral tradition relates to the counting of sheep, during the most frenzied moments of shearing. There are several different rules and interpretations of it, depending on the region where it's played. It's almost a dialectal music and it's pretty common to see people playing it, in the streets of small villages of the island. There are lots of passionate fans, it's perpetrated from generation to generation; it's a game of numbers and concentration, rules and manual skill, it encloses the true tradition and has no boundaries.
The common rule, is that the participants have to guess the sum of the numbers showed with the fingers by the players. Who guess the sum showed by the challenger gain a point, if they both guess correctly no one gets the point and the game goes on, until someone reaches a previously agreed score.
It's interesting to point out that the players tend the arms at the same time, they show a closed fist to symbolize number one or tense a number of fingers of their choice. In the meantime, almost to intimidate the opponent, they shout in local dialect the total sum they think is correct. Very colourful dialectal expressions are often used, different for every region, giving the game several facets.
Sa murra can be played one on one or in couples, but the last one is the most common in Sardinia. Someone play sitting, others play standing, a table can be used or not, someone make a break after a point is scored and others play constantly. Sometimes a recently introduced and important role is involved, Su Contadori (the counter), especially in the most important tournaments that take place in Oniferi, Fonni and Urzulei. He's a sort of referee, his task is to count the points, verify the real amount of the sums showed by the players, deal with possible irregularities.