RBI delivers the secret instructions to dedicated rupee traders in soundproof rooms.Some days the orders focus on size: sell $100 million every minute. Other times, it’s about market levels: sell everything until the target is hit. And on certain days, the instruction is simply to step aside.The hard-to-predict intervention strategy is part of the Reserve Bank of India’s increasingly high-stakes attempt to manage the rupee as it weakens to all-time lows.Interviews with bankers, traders and former central b ...