Polish 1♣

This Polish Club has 3 variants:

12–14, 2–4♠, 2–4♥, 2–4♦, 2–4♣
11–17, 5+♣ or 4414
18+, not suitable for 1♦

Note that 2♣ is no longer natural since Polish Club 2020: Expert. 1♣ takes care of all ♣-suited hands.

I move diamond invitation down to 1♣-2♠ in case of a misfit. Strong balanced hands go to 1♣-3♦ and 1♣-1♦.

I also swap 1♣-2♣♦ because the potential club fit saves bidding space. On the other hand, the diamond suit requires more space to explore a fit.

1♣-	Quasi-NAT or 18+
1♦!	(R), 0–11 or BAL 16+
1♥	F, 7+, 4+♥
1♠	F, 7+, 4+♠
1NT	BAL CONST, 8–10
2♣!	FG, 5+♦
2♦!	FG, 5+♣
2♥!	P/C, 7–9, 4–5♥, 5=♠
2♠!	INV, 9–11, 6+♦
2NT	BAL INV, 10–11
3♣!	INV, 9–11, 6+♣
3♦!	BAL FG, 12–15, 2–3♠, 2–3♥, 3–4♦, 3–4♣
3M!	PRE, 3–6, 7+#
3NT	BAL, 12–15, 33(43)
4♣!	PRE, S-SOL 8+♠♥, 0–1 outside A/K
4♦!	PRE, SOL 8+♠♥, no outside A/K
4M	PRE, 8+#

P-1♣

Game-forcing responses simplify to corresponding invitations. Preempts also become invitations due to failure to open.

P-1♣-	Quasi-NAT or 18+
2♣!	INV, 5+♦, 0–3♠, 0–3♥
2♦!	INV, 5+♣, 0–3♠, 0–3♥
2♠!	INV, 9–11, 5+ 4+ minors
3♣	INV, 9–11, 6+♣
3♦♥♠	STR INV, 10–11, 6+#