The internet is filled with things. Here are some of them.
The borders of Fukushima, Niigata and Yamagata doesn’t meet at a tri-point as the zoomed-out map seems to suggest. Instead, you will see a very thin strip of land attached to Fukushima snaking into Niigata. This is called a salient. The Fukushima Prefecture salient —famously called the umbilical cord—extends about 8 km starting from the summit of Mount Mikuni, following the ridge of Mount Kengamine, passing through the summit of Mount Iide, and ending on the summit of Mount Onishi. At its narrowest, it is only about 35 inches across (90 centimetres).The article explains how this came to be, which can be summed up as: the ridge of this mountain range is culturally important to Fukushima Prefecture, so much so that it was made to remain inside its borders even when the surrounding land was reassigned.
Linked is a compelling argument that we don't really know how many people there are in the world. Countries with weak central governments, difficult terrain, and politicized incentives to adjust population numbers make for wildly unreliable population counts. Some countries don't even attempt to collect census data and yet report population numbers anyway.
The map continues to not be the territory.