Features:

• 1♣ opening:

  • • 11-14 HCP, no five major, no six clubs and no five clubs with a side four;

    • 11-17 HCP, 4-4-1-4 with singleton ♦;

    • 15-17 HCP, 5+♣ balanced;

    • 18+ HCP, any hand,

Some sequences:

1♣ - 1♦:

• • • • • 0-6 HCP, any shape;

        • 7-11 HCP, no majors;

        • 17+ HCP, no majors,

1♣ - 1♦ - 2♦ - very strong opener rebid, game force:

• • • • • 2♥ - 0-3 HCP (A, K or Q only);

        • 2♠ - 4-6 HCP, transfer to NT;

        • 2NT - forbidden:

        • 3♣ - 6+m;

        • 3♦ - 6+♥;

        • 3♥ - 6+♠;

        • 3♠ - minors,

1♣ - 1M - 2♦ - odwrotka

1♣ - (1♠) - X - 2♦ - odwrotka

1♣ - (P) - 1♠ - (2♣) - 2♦ - odwrotka

Odwrotka is always if partner shows major and bidding is under 2D. 

Answers after odwrotka:

• • • 2♥ - 4M, 7-10 HCP;

    • 2♠ - 4M, 11+ HCP;

    • 2NT - 5M, 7-10 HCP;

    • 3♣ - 5M, 11+ HCP;

    • 3♦ - 6M, 7-10 HCP;

    • 3♥ - 6M, 11+ HCP;

    • 3♠ - 7M, 7-10 HCP;

    • 3NT - 7M, 11+ HCP;

    • 4♣ - 8M, 7-10 HCP;

    • 4♦ - 8M, 11+ HCP;

    • 4♥ - 9M, 7-10 HCP;

    • 4♠ - 9M, 11+ HCP,

• 1♦ opening:

  • • 11-17 HCP, 5+♦;

    • 11-17 HCP, 4-4-4-1 with singleton ♣;

    • 11-14 HCP, 4♦ i 5♣.

• 1♥ and 1♠ opening:

The 2♣ question by the respondent is not used due to its low popularity, low effectiveness and unnecessary complication.

• 2♣ opening:

  • • 2♦ - 10+ HCP, ask for majors:

      • • 2♥ - four ♥;

          • • relay 2♠ - further ask about the three:

              • • 2NT - 34x5;

                • 3♣ - x4x6;

                • 3♦ - 1435 lub 0445;

                • 3♥ - 2425;

                • 3♠ - 44x5,

        • 2♠ - four ♠ 

          • • relay 2NT - further ask about the three:

              • • 3♣ - 4xx6;

                • 3♦ - 4135 lub 4045;

                • 3♥ - 43x5;

                • 3♠ - 4225,

        • 2NT - 11-12 HCP, 6 ♣, balanced;

        • 3♣ - 6♣ and singleton;

        • 3♦ - 13-14 HCP, 6 ♣i i 4♦;

        • 3♥ - 13-14 HCP, 6 ♣, singleton ♥;

        • 3♠ - 13-14 HCP, 6 ♣, singleton ♠;

        • 3NT - 13-14 HCP, 6 ♣.

    • 2♥ - 7-11 HCP, 5 ♥, non forcing;

    • 2♠ - 7-11 HCP, 5 ♠, non forcing;

    • 2NT - 5-9 HCP, transfer for ♣ or 14+ HCP, 5-5:

      • • relay 3♣:

          • • 3♦ - 5+♦ and 5+♥, forcing;

            • 3♥ - 5+♥ and 5+♠, forcing;

            • 3♠ - 5+♠ and 5+♦, forcing,

    • 3♣ - 11-12 HCP,  inviting;

    • 3♦/3♥/3♠ - 11-13 HCP, 6+, inviting.