Well...

These are fare classes and how they relate to mileage accrual/class of service bonus. I'm not sure what classes NH books awards/upgrades into.

As per the ANA USA Platinum Desk on 9/3/04:
Class of Service Bonus:
150%=F, A
125%=C,D,Z, and sometimes J
100%=Y
70%=B, H, K, L, Q, S, W also M’s from USA and G’s from Japan
50%=G’s from USA and M, T from Japan

Overall you can see the general allignment with UA.
F Full Fare First
A Discounted First
C Full Fare Business
D Discounted Business
J (I've never seen an NH J class)
Z Biz Wari is ticketed in Z class
Y Full Fare Economy
B This usually allows a change to the return date with a 20,000 fee
H
K
L
Q
S
W
M,G,T (assorted discounted fares based on origin)

Once you get below the Y, you begin to run into an assortment of rules pertaining to upgrade eligibility which differ based on ticketing region.

Anyone else want to take a stab at this?

Scho