Natural 1♥

The major suit openings show 12–17 points and 5+ cards. I separate them into two chapters due to subtle differences in their continuations.

Responses to 1♥ are similar to natural 2/1 along with reverse Bergen raises.

1♥-12–17, 5+♥
1♠F, 4+♠
1NTNF, usually 7–11, 0–3♠, 0–3♥
2♣♦NAT FG
2♥CONST, 3+♥
2♠!UNBAL INV, 9–11: 3=♥ or 5+ 4+ in minors
2NT!FG, 4+♥
3♣!INV, 4+♥
3♦!CONST, 4+♥
3♥!PRE, 4+♥
3♠!FG SPL, 0–1♠, 4+♥
3NT!Choice of games, 12–15, 33(43)
4♣!FG SPL, 0–1♣, 4+♥
4♦!FG SPL, 0–1♦, 4+♥
4♥!PRE, UNBAL 4+♥

P-1♥

P-1♥ reduces to a fairly natural system. We can keep using Stenberg 2NT because it assigns minimum hands to 3♣.

P-1♥-12–17, 5+♥
2♣♦INV, 5+#
2♠!UNBAL INV, 3=♥
2NT!INV, 4+♥
3♣♦!INV, 5+#, 4+♥
3♥!CONST, 4+♥