North has a difficult decision, to open 1♠ or pass. Only 10 HCPs, not meeting the rule of 20 (HCPs + length of 2 longest suits should be 20 or more, but it is only 19) and vulnerable. However it is position 1, there is a relatively good rebid with 2♣   (weak opening with 5+♠ s and 4+♣ ) or 2♠ s, and the hand is far stronger than 10HCPs (Kaplan hand evaluator = 11.5HCPs). So..

Over 1♠ 

East can either pass or bid 2♦ (only 1HCP in ♦ s) and being vulnerable a pass is probably correct.

Depending on the sysem being used South needs to do a forcing bid.

Using advanced methods a Jackoby 2NT is ideal. The responses are:

3 of trump suit is strong and balanced, but 4 of the trump suit is weak. This is an example of slow arrival in a focing sequence is stronger than quick arrival.

3 of another suit shows a shortage (singleton or void).

4 of another suit shows a second suit.

So after South bids 2NT

North will jump to 4♠ as they had a very weak opening hand.

Over North passing

East can either pass with 10HCPs bid 1♦ or bid a weak 2♦ . In position 2 one should have solid bids unlike in positions 1 and 3. More importantly it is a poor 10HCPs Kaplan evaluator = 10HCPs. So pass should be the bid.

South with 15HCPs will open with 1♦ (too strong for 1NT)

West may consider a weak 2♥ bid (but no 1st or 2nd rounf contriols) it is a poor hand vulnerable so should pass.

North will bid 2♠ that South will raise to 4♠ 

Using Simple Systems

Over 1♠ by North South should not bid 4♠ which is a shutout bid that may miss a slam.

3♠ which is invitational risks a pass.

So best to do a delayed game raise to show a strong hand with ♠ s

Do this by bidding 2♦ with the aim of bidding 4♠ .

Over 2♦ North will show they are 5+♠s and 4+♥ s and weak.

South will then just bid 4♠ s

Over North passing

South will bid 1♦ and over a bid of 1♠ by north will jump to 4♠ as North did not open N/S will not miss a slam.

4♠ s makes.