Some of India’s top chess stars allowed themselves a brief break from training on Sunday to celebrate the birthday of Arjun Erigaisi. It was a small celebration, these days time is at a premium for India’s top chess talents: R Praggnanandhaa, D Gukesh, Vidit Gujrathi, Erigaisi and Pentala Harikrishna. But after the celebration, the players were back at work, cramming in some team work before they prepared to face off each other at the Tata Steel Chess India tournament, which started for them on Tuesday. “Arjun’s birthday was a nice social event, for which we all came together. It had…