I wish I had your luck. What route did you fly?
I've done ORD-NRT x1, NRT-ORD x2, and FRA-NRT x1 in NH F, all on 77W's, and the fewest I've had was 4 in F; My 2 most recent trips (FRA-NRT and NRT-ORD, both in December) were full in F and had 1-2 C seats open.
I have not had the same luck others have had when doing trips in F and most of my trip in F have been at least 40-50% full. I've had a couple LH 744 trips with only 3-5 of us in F. I've never had an LH 333 with less than 5 in F.