According to Official Guinness Records,
The Most dice stacked on the back of the hand in 30 seconds whilst balancing on a balance board is 12, achieved by Silvio Sabba (Italy) in Rodano, Milan, Italy, on 3 January 2017. Silvio Sabba is a serial record breaker. This record was broken at the New Fitness Point Gym.
For a complete list of 2017 records, please visit 2017 Guinness Records in Italy.