Originally Posted by
Selendia
I think your checkering bags go straight to destination, but they will make you go through a transfer security checkpoint, and scan your carryon
Do you have Sky Priority? If so, you'll be fine. If not, the line seemed long to me. They had 4 or 5 lines, but the x ray machine had a very short "landing" and people seemed slow to take out their computers and remove their coats (one at a time). US airports seem to have a larger landing so 2-3 people are unloading at the same time.
This is all very true, security at NRT can be kettle heaven. The lines often move slow but they do move. Presuming the OP is flying economy, IME the time from aircraft to clearing security is about 20-40 min, depending on how many aircraft are arriving at the time, how far back the seats are, and how fast the OP can walk to security.
In any case, 70 min is more than enough time but probably won't allow any time for shopping or lounge.