Why is Vidarbha considered 'gateway to power' in Maharashtra elections?

Maharashtra's Vidarbha region is called 'gateway to political power' as the party that wins there usually forms government in the state. It has 11 districts and contributes 62 seats in the 288-member house. It was a Congress bastion until BJP made it its stronghold and the parties have fielded 40% and 33% of their candidates, respectively, from Vidarbha.