In this Sept. 1, 2014, photo, a clock hangs on the wall as North Koreans leave an underground train station in Pyongyang, the capital.Wong Maye-E/The Associated Press
It was a small slip in an interesting story about North Korea's plan to introduce a new time zone and blot out reminders of Japanese rule.
The article confused latitude and longitude (one of those things I can never get straight without looking it up). Degrees of latitude are horizontal lines that go north and south from the equator. Degrees of longitude are the vertical lines that affect time zones.
The reader who spotted that mistake was Alain Gingras, a retired Canadian diplomat who spent many years in Southeast Asia and has an encyclopedic knowledge of many things. I wrote about him recently.
"Also, you lost a good occasion to inform your readers that the whole of China is running on a single time zone and, of course, no summer time. I was told it is because it is very important for people in China to eat their meal at the same time, every day," Mr. Gingras wrote to the reporter.
In Pyongyang, North Korea, the clocks will be set back half an hour on Saturday. Of course, we in Canada know all about the half-hour time difference in Newfoundland. But did you know that there are also quarter-hour time differences.
In his note to me, Mr. Gingras said you must be careful with the ¼-hour time zone. "Beside Nepal (+5¾), there is Caiguna-Eucla, Western Australia (SE) (+8¾). Real amateurs also know about Chatham Island (+12¾). I did not check them recently but they were correct when I made my list (yes!) a while ago."
And in case you need it for a trivia contest, did you know about Antarctica. "If you want to lose your mind on this topic, check Antarctica," Mr. Gingras wrote. "To preserve your sanity, I will tell you right away: They use the time of the base which supplies them."
In Wednesday's paper, there were two other errors, both related to geography, noted by a few readers.
An article on Japan restarting its nuclear technology four years after the nuclear meltdowns in Fukushima incorrectly said in the headline that the country would restart the Fukushima reactor. However, the story accurately says the reactor at the Sendai Nuclear Power Plant in Kagoshima Prefecture would restart. That power plant is on the far south of the island while Fukushima is in the north. Japan has made it clear that all Fukushima nuclear power reactors have been permanently closed and are in the process of being demolished. And several Globe readers knew that.
The other mistake was in a map with the story on military exercises on both sides of the NATO-Russia border. The map showed members of the North Atlantic Treaty Organization in blue, but it included Sweden, which is not a NATO member.
On Thursday, a woman wrote to me saying: "To the best of my knowledge, Sweden is not a NATO member. I was surprised your Thursday edition did not include a correction."
The error was corrected in Friday's paper, thanks to her knowledge and diligence in writing in.
You learn something every day dealing with Globe readers.
Sylvia Stead