| 1♣, 1♦, 1♥, 1♠ | 12 – 19 | 4+ cards |
| 1NT | 15 – 17 | balanced hand (max 1 doubleton, can be 5 cards major suit) |
| 2♣ | 23+ | or 3 loosing tricks, FORCING |
| 2♦ | 5 – 10 | (mini multi) 6 cards in Hearts or Spades |
| 2♥, 2♠ | 5 – 10 | Muiderberg – exactly 5 cards and 4+ unspecified minor suit |
| 2NT | 20 – 22 | balanced hand (could contain two doubletons) |
| 3♣, 3♦, 3♥, 3♠ | 5 – 9 | pre-emptive 7+ cards |
| 3NT | solid 7-8 cards minor suit | |
| 4♥, 4♠ | 6 – 8 | pre-emptive, solid 8+ cards suit |
- Rule of 15 – on last position You should open the bidding if the number of high card points and the number of spades equals fifteen.
- Rule of 20 – you can open the bidding when your high-card point-count added to the number of cards in your two longest suits gets to 20.