With only one road to home, take it

Douglas Adams, in The Hitchhiker's Guide to the Galaxy, wrote, "Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."

When you are declaring a bridge deal, you try to find the safest road to make your contract. However, even if you choose the one that is mathematically best, you might end up in a black hole, going down because you were unlucky. Still, it is amazing how in bridge columns, the right approach works!

What should South do in four hearts after West cashes his two top spades, then shifts to the diamond jack?