Interval, Interval of Time, Interval of Space
There's a gate that the sun goes through at a regular interval. There is an interval of time in the sense that the sun goes through it at the same time every day. And there is an interval of space in the sense that it has to go through the space between the gate posts.
"Interval" is a weird word to remember, but just think of the sun going around the earth and through the gate like clockwork. Every 24 hours it passes through the gate, and each interval is exactly the same.
かん, けん
あいだ, ま
None
This method of keeping track of intervals of time was invented by the great Khans of Mongolia, specifically the most famous Khan of all: Genghis Khan (かん). Genghis Khan has had a huge impact on the world as we know it, especially the Eurasian continent of the past, so he's going to come up a lot from now on. Be prepared to get very familiar with him and his friends!
Picture Genghis Khan ordering his most skilled inventors and builders to create this special sun gate so they can harness the power of intervals, and all people under his rule can benefit from the accurate telling of time.