Artic Left button bar and right panel

Over opponents 1NT, it is important to get into the action with a suitable hand.
Here you are showing the Majors, with either 5/5 or 5/4, or you have a 6-card suit
Note the hand is not strong enough to double.
The object of bidding is to compete for a part score without taking too much risk.
It is important to have your points in the suits and not have other defensive tricks

MODIFIED ASTRO

Opponents open 1NT. A bid of:-

2♣ Guarantees 4 hearts(could be 5) and 5 of another suit

Responses

With 4 card- Heart support. Bid 2/3/4♥ according to strength.

under 4-card support bid 2♦ as a relay. Partner will now bid his 5-card suit (or will pass if the other suit is Diamonds)

2♦ Guarantees 4 spades(could be 5) and 5 of another

Responses

With 4 card Spade support bid 2/3/4♠ according to strength

Under 4-card support bid 2♥ as the relay bid.

2NT shows both minors

2♥ /♠ or 3♣ /♦ shows single suited hand