A mafia boss on the run since 1993 communicated with fellow criminals using a code based around sheep, Italian police say.
Officers arrested 11 men they say are linked to the fugitive head of the Sicilian Mafia, Matteo Messina Denaro.
They said Mr Denaro communicated with his henchmen using scraps of paper left at a farm in western Sicily.
Phone messages used to alert the men to new bits of paper or "pizzini" often referred to sheep, police say.
Officers do not believe that the alleged criminals were really discussing agricultural matters.
"The sheep need shearing," "The shears need sharpening" and "The hay is ready" were among the messages passed between mafiosi, police say.
Another said: "I've put the ricotta cheese aside for you, will you come by later?"
La Stampa said (in Italian) that the men were filmed by police over several months. La Repubblica said cameras had been installed in trees to film the men.
They were arrested in raids across Sicily early on Monday. Three of those arrested were over 70 years old.
Mr Denaro has been on the run since 1993 and is seen as the successor to two jailed Mafia godfathers. He once boasted he could "fill a cemetery" with his victims.
Italy's Prime Minister Matteo Renzi praised investigators in a post on his Facebook page, adding: "Italy is united against organised crime."