Where does “あさいち” come from?

あさいち (Japanese) comes from Japanese 一番, from Japanese 一, from Japanese 始め, from Japanese 始める — begin; start; initiate; originate.

あさいち (Japanese): (being the) first thing (done) in the morning

Definitions

あさいち traces back through 3 separate lines of ancestry.

Step	Language	Word	Meaning
1	Japanese	一番	first, number one; game, round; most, -est, -most
2	Japanese	一	one, 1; "term relating to the number one"; unity
3	Japanese	始め	beginning, the start of an activity or time...
4	Japanese	始める	begin; start; initiate; originate

Step	Language	Word	Meaning
1	Japanese	朝	the morning; the morning, morn; the morrow, next...
2	Old Japanese	朝	the morning, morn; the morrow, next morning
3	Proto-Japonic	asa	morning

Step	Language	Word	Meaning
1	Japanese	市	market; city
2	Old Japanese	市	—