Hand 4 - 1NT or 1 Spade?

This is chapter 4 in the story of my attempt to determine if it is better to open 1♠ or 1NT with 15 to 17 HCP and a five card ♠ suit.

The journey started with this post:
Later On

Here is the fourth hand I generated:

	North ♠82 ♥KJ76 ♦QT6 ♣KT63
West ♠KQT65 ♥AT3 ♦A4 ♣QJ9		East ♠J973 ♥Q985 ♦53 ♣852
	South ♠A4 ♥42 ♦KJ9872 ♣A74

Dealer is West and everyone is vulnerable.

Double Dummy:
1NT can make by N/S!!!
2♠ makes by E/W
3♦ makes by N/S

Analysis

If West opens up 1NT, North will pass and East will pass. Will South come in?

If South does come to show ♦ West will probably bid 2♠. North can raise to 3♦. Will East compete with 3♠? Will they feel this shows more values? Perhaps not but let's say they do. N/S are unlikely to double so down 1 (minus 100) is better than letting the opponents make 3♦ (110).

If West opens 1♠ again North and East will pass. Will South come in?

If South does come to show ♦ West will either pass or potentially Double to say "Bid Partner". I don't think they are strong enough to do this but whatever West does North will raise to 3♦. Will East compete with 3♠? They are more likely to do so in this auction since they have already denied having any useful values at all with the original "Pass". Plus East knows they do have a nine card fit and this is their LAW level. N/S are unlikely to double so down 1 (minus 100) is better than letting the opponents make 3♦ (110).

So all things are pretty much even (I am slightly favouring 1♠ because East's original pass will show a much weaker hand over a 1♠ opening bid vs a 1NT opening bid) IF South comes in.

What if South does NOT come in?

What happens then?

If South passes West's opening bid (whatever that might be), West will go down in 1NT but make 1♠.

So this one I think is better to open 1♠ because if South does not bid you are better off playing in ♠.