The system is based on Optimal Hand Evaluation, a method for applying corrections to the 4-3-2-1 honor point count. Darricades has two books on hand evaluation: Optimal Hand Evaluation and Optimal Hand Evaluation in Competitive Bidding. I recommend reading those books before Optimal Precision Relay although the book also contains a summary of the hand evaluation approach. Optimal Precision Relay uses a relay structure and transfers over most opening bids. The span for the opening bids other than 1♣ is at most 6 points and the system allows the opener to further narrow his strength to a 3 point span after relays allowing you to stop early when needed. Summary of the opening bids: 1♣: 18+ HLD (Honor, Length, Distribution points), forcing 1♦: 14-19 HLD, minor two-suiter or 5+ ♦ and 4 ♥ or 4♠ or 15-17 HL (Honor, Length points) balanced 1♥/♠/: 12-17 HLD 5+ cards or 4♥ and 4♠ 1NT: 12-14 HL balanced 2♣ to 2♠: 15-17 HLD, 6+ cards, single suiter 2NT: 12-14 HLD, 6+ ♦, single suiter 3♣: 12-14 HLD, 6+ ♣, single suiter 3♦ and up: pre-emptive transfer bids