East will open 1♣ 

South will pass

What should West do?

1♠, 2♠,3♠ or 4♠ ?

1♠ is probably best, as less likely to miss a slam.

2♠,3♠ and 4♠ are normally taken as weak and 6, 7 or 8♠ s. 

So 4♠ is the main alternative, but with only 5 losers, you only need East to supply 4 winners and you have a slam. Losing tricks is a usefull approach to evaluating hands in suit contracts.

North with both the other two suits will double, which is far better than a 2♦  overcall.

East with a minimum hand and little to say will pass.

South with less than 8HCPs will bid 2♥ 

West now know there is little chance of a slam so will punt 4♠ or invite with 3♠ .

4♠ here is the winner as it makes and 3♠ invite will be passed by East.