Polish 1♣

This Polish Club has 3 variants:

12–14, 2–4♠, 2–4♥, 2–4♦, 2–4♣
12–17, 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 invitational hands out of 1♣-1♦ relay to make it non-forcing. I believe this method is more resilient to interference.

1♣-	Quasi-NAT or 18+
1♦!	ART NEG, 0–9. BAL S/T, 15–17, (32)44
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+♣ or 5+ 4+ minors
2NT	BAL INV, 10–11
3♣!	BAL FG, 12–14 or 18+, 2–3♠, 2–3♥, 3–4♦, 3–4♣
3♦!	INV, 9–11, 6+♦
3M!	PRE, 3–6, 7+#
3NT	BAL S/T, 15–17, 33(43)
4♣!	PRE, S-SOL 8+♠♥, 0–1 outside A/K
4♦!	PRE, SOL 8+♠♥, no outside A/K
4M	PRE, 8+#

1♣-3♣♦ and 1♣-3M look unrelated, yet they serve the same purpose: move the best single suiters out of 1♣-1♦.

P-1♣

Game-forcing responses simplify to corresponding invitations.

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