Strange things happen on cruise ships. You go to interesting places – and some that are not so interesting. You meet interesting people – and some whose company you would willingly swap for a plate of gefilte fish or a good shluf.

I have been there and done that. Jewish places and Jewish people are not immune from any of it.

The Americans like to talk about what they call "Jewish geography". There was a lot of that on the ship I have just left.

It was the journey when a Canadian lady told me, only partly joking: "I think there are more Jews on this ship than in Montreal."

So you add her countrymen to a larger number from the US, a sprinkle from the UK and other places and you have a Jewish geography lesson.

But what I have just experienced is somewhat different. You could better describe it more simply as Jewish genealogy.

It happened on the first night. When I was directed to a certain table, I assumed (wrongly) that I was there for the length of my three-week stay on the journey from Los Angeles to Tokyo.

It was not the most exciting prospect. There were three (very) old ladies at the table, a gentleman of, shall we say, senior years, and a dance host.

I tried to make conversation generally, but not altogether successfully. In desperation, I turned to the lady on my left, who had previously kept more to herself than the others. She told me she was a mere 90 years old, had had a wonderfully happy 70-year marriage which had only fairly recently come to an end with her husband's death. He had been a well-known journalist on a prestigious American magazine. Together, they had travelled the world.

The other diners had given up on me as much as I had given up on them. So the lady, rejoicing in the name of Sherry (a liquor she didn't seem to touch) and I, switched to a little small talk.

Did she have any contacts with Britain? Yes, she said, she had family in Scotland.

OK, so did a lot of people. And, she told me, she had visited London many times. She loved it. I was, of course pleased to hear that. But most of the voyagers had done the same. And, she added, she used to have a cousin who moved to London.

"Where in London had your cousin moved to?" I asked Sherry, only, I have to admit, to continue our small talk. "Regent's Park," she said. "Yes," I said, "I know Regent's Park".

"That was where my cousin lived," she added. "Mina moved to Regent's Park when she got married."

Suddenly, there was an icy streak starting to run down my neck. "Would you say that again?" I asked. "My cousin Mina moved from Glasgow to Regent's Park," she repeated, embellishing the news slightly.

I think the colour drained from my face. "Mina? Did you say Mina?" It was an unusual name. I wanted to be sure. Yes, that was her name. I am sure I blinked. "I think you are talking about my aunt," I said.

Her colour had changed too. "She married a man who made ties," she said, shaking slightly, I thought. "Yes, my Uncle Jack," I spluttered. "He was my mother's brother".

Suddenly, there was something to tell the other people at the table. More, to write home about.

"We always went to their lovely flat when we were in London. Jack always gave ties to my husband". As he did to me and I hadn't bought a tie quite as good for years.

"We were wonderfully entertained by them." I didn't add that that was more than we were. But blood is blood. Jack had my DNA. Yes, my mother's brother. Her mother was Mina's mother's sister. Or her brother. Or was it the other way round? It didn't matter.

Coincidence? I can't stop thinking that if I hadn't been put next to this charming complete stranger and, instead, sat next to one of the other ladies, I would never have known any of this. One of the degrees of separation that had suddenly come together would have stayed... separated.