And so, so then: vậy là / thế là

In a story, vậy là moves on to what happened as a result: "and so", "so then". Xe hư giữa đường, vậy là tụi em phải đi bộ. The bike broke down on the way, so we had to walk. In Hà Nội people say thế là, and you'll hear that in Saigon too.

It's for telling what happened, often something unplanned: the second event follows naturally from the first. Em ngủ quên, vậy là trễ chuyến bay. I overslept, and so I missed my flight.

It also sums up where things stand now: Vậy là xong! So that's done! Vậy là mình hết tiền rồi. So now we're out of money.

Two neighbours look alike. Vì vậy (that's why) explains a cause and its result, and suits work and writing: Đường đang sửa, vì vậy xe buýt đi đường khác. Vậy thì (in that case) leads to a suggestion or a decision: Vậy thì mai mình đi. Then let's go tomorrow. Vậy là reports what happened; vậy thì proposes what to do.