James Bach and how I Enjoyed his Visit to Switzerland

Some weeks are boring, some weeks are frustrating, some weeks are just regular. But once in a while there is a week filled with exitement, learning opportunities, joy and intellectual challenges. I am a lucky guy because I happen to have lived such a pleasurable week recently. James Bach came to Switzerland for the first time.

His flight was coming in from England where he attended several appointments in Cambridge. I was waiting for him to exit into the arrival hall. As expected it took not long for James to drop a puzzle bomb on me. It goes as follows:

  1. You have a range of integers from 2-180
  2. Two integers x and y are chosen from the range (x and y may be equal or different)
  3. A person A is given the sum of x + y
  4. A person B is given the product of x * y
  5. First, person B says to person A: “I don’t know your sum”
  6. Then, person A says to person B: “I already knew that you do not know my sum”
  7. To which person B replies: “Now I know your sum”
  8. And then person A says: “And now I know your product”

Question: What is the sum of x + y, what is the product of x * y and what are the values of x and y
A hint: It is possible to solve it by the sole use of your brain, a sheet of paper and a pencil

IMPORTANT: Please do not leave the solution in the comments below

While driving James to his hotel I tried if there was a simple solution to the puzzle but I could not find one so I decided to attempt to solve it as soon as I got home. Also, it is not such a good idea to try to solve puzzles while driving.

In the hotel we had some more testing discussions before James retired to his room and I was very eager to get back home to solve his puzzle. I think I was on a good path towards the solution but I decided to give me a break because I was stuck somehow.

Interesting enough, the brain seems to have its playful free time during sleep. My brain decided to wake me up at about four a clock in the morning giving me a hint about how to solve it. I decided to get some more sleep and just took some notes on the general idea. Later in the morning I solved the puzzle which made me kind of proud. Tricky one, this one!

Sunday afternoon I picked up James from his hotel and we strolled through Zurich while he entertained me with a lateral thinking puzzle involving a waste dump. Again I enjoyed it very much and it gave me the appetite for the dinner. James is very good at challenging your thinking.


Monday morning we took the train to my workplace Phonak AG, where James spoke all day about tester self-education and did many puzzles with the audience of about 50 people. The astonishing thing was that there were more developers present than testers. What a great success for software testing. Developers become more and more interested in what we do. We testers have won! (Just joking, I love you all, dear developers)


This year’s Swiss Testing Day saw an amazing record breaking number of 800 participants. James had the first of the keynotes in the morning (you may see the video here) and I hope he inspired many testers to become interested in the context-driven school and self-education. I expect to see more Swiss testers working on their reputation in the future.


We sold James’ excellent book Secrets of a Buccaneer-Scholar at our conference booth and every 10th person at the conference bought a copy. That, too, gives me hope that there are more context-driven people in Switzerland. If you - dear reader - are one of them, please contact me immediately. I want to get to know you and talk to you. James talked all day to many people, there were dice games and his hand must have been tired from all the book signing.

Thursday was a work day, we went through some of my Skype coaching transcripts and James gave me a lot of valuable feedback. We did that in one of my favorite coffee shop/book store Sphères in Zurich. It is the perfect place for productive work.


Friday came and James was very eager to learn about Swiss cheese. We drove to Engelberg where there is a public display of cheese making located in a monastery. In the middle of a room there was a kind of glass igloo where a cheese maker was doing his stunts while the visitors pressed their noses flat on the outside. A bit like in a zoo, but without animals.


In Engelberg we found the wonderfully victorian Hotel Terrace from where we had a beautiful scenery of mountains. Again we went through more coaching transcripts and tried to identify patterns.


After coming back to Zurich, we ended our day with a dinner at the Prime Tower on the 35th floor and challenged each other with some more lateral and mathematical puzzles. James also made fun of me because I was eating my hamburger with fork and knife. See, that’s us Swiss people behaving at a fancy restaurant. Anyway, great day, but then we were both tired at the end. It was like in Monty Python’s “Just a thin mint”-scene (Caution: this link is not suitable for the faint-hearted), one more puzzle and my brain might have exploded.

James headed off to Stockholm on Saturday, I said good bye at the airport and I hope he comes back to Switzerland soon. You’re always welcome, my friend.

BTW: Here is the link to James’ view on his visit to Switzerland.

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