Latitude
The thread that goes through Korea is the latitude line splitting up North and South Korea.
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ぬき, よこいと
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The only way you can see this latitude line is to ride an eagle (い) over it. The line isn't visible from a car, you're too close, and a plane is too high. You have to see it from an eagle's point of view.
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Finish up what ever you are doing on the other tab(s), then close them to continue.
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