Rule making power for GST: comprehensive authority to prescribe valuation, credits, registration, compliance and enforcement procedures. The provision vests the Central Government or State Government with a broad power to make rules, on the Council's recommendation, to implement the Act including the limited power to give retrospective effect on first exercise; enumerated rule making topics include tax rate and place of supply determination, valuation and trade discounts, input tax credit conditions and transitions, registration and migration processes, assessment, recovery and provisional attachment, recordkeeping and returns, inspection and audit, refunds and export rebates, enforcement measures including compounding and penalties, and related administrative appointments and procedures.