Muiderberg 2M

Muiderberg shows exactly 5 cards in the bid major and a side minor suit. Multi 2♦ already takes care of 6+ cards.

2MPRE, 5+M, 4+m
2♠NAT NF
2NT!INV+, ask for the minor suit
3♣!P/C
3♦!INV+, 3+M
2M-2NTINV+ (R)
3♣MIN, 4+♣
3♦MIN, 4+♦
3♥!MAX, 4+♣
3♠!MAX, 4+♦