If you step over a comb, you won't get married

Antique combs in Japan are very ornate and precious objects - there's even an unofficial "Comb Day" on September 4th every year. September is the ninth month and the Japanese for nine is ku. The Japanese for four is shi and the Japanese for comb is kushi.

Combs were particularly special because the ancient hair style for women was long straight hair (taregami), a style loved by men even today, but required utmost attention for the women. Daily grooming was essential to keep its beautiful appearance, and that was only possible with a good comb.

In those days, room furniture was sparse and women would kneel on the floor to preen their hair. It was natural to lay the comb on the tatami floor when they'd finished, but great care was taken to never step over the comb. If they did, their future marriage was in serious jeopardy.

In Japanese, kami means God, or gods in general, deities and spirits. And they of course must not be offended. The same word kami means hair, and so much lengthy brushing invariably means some strands of hair will remain in the teeth of the comb.

Other meanings for kami are "bite" and "above", and by extension, the angry bites from the gods above. Stepping over the comb on the floor is particularly offensive.

Verity:

The "bite" and "above" meanings of kami are perhaps not in daily use as often as "hair", but there's a further meaning of kami which is probably as common as "hair", and that other meaning is "paper".

So to our first question: Why should it be believed that gods get upset if somebody steps over a comb which may, or may not, contain a few strands of hair, but not get upset if somebody steps over a piece of paper? The amount of hair-kami in a comb is negligible (by weight or volume), if any, compared with paper-kami, which is 100%.

And our second question: If the woman cleans a comb and tosses any strands of hair into the fire, do the gods not mind?

When it's believed that gods are upset, why should the punishment be the inability to get married? Why not some other misfortune?

And if the woman is already married when she steps over a comb (or piece of paper), what happens then?