From NYB:

The beginnings of Nankai

Nankai Tekko KK, Techno Nankai was established in 1923 in Hamamoto
cho, Sumiyoshi-ku, Osaka, Japan as a bicycle parts factory. We focused
especially on coaster brake hubs and exported them mainly to the
South-East Asian region. Since 1959, we exported our coaster brake
hubs to USA; a major consumer in the world. We were the very first
Japanese bicycles parts company to do so. The top 3 coaster brake hub
manufacturers at the time were, Torpedo (Germany), Bendix (USA) and
Nankai (Japan). Nankai has been renamed and is now known as NYB.

What are major features of the new hubs?

The major feature is the angular bearings that reduce friction and
maintain speed even when the axle is slanted at a 30 degrees angle.
Commonly used radial bearings are not designed for that use. In the
case of BMX riding, radial bearings will wear down rapidly and they
are unadjustable. Although our coaster hubs require adjustments before
use, we have known users who have ridden them for 20 years.

What has been improved from the old hub?

First, the clutch’s reliability has been improved to prevent cranks
from catching while coasting backwards. Secondly, the weight has been
reduced.  The new FCH-K-MX3/8 hub is 100 grams lighter compared to the
AKA3/8 hub. While the new FCH-B-MX14mm hub is 44 grams lighter
compared to the ABA14mm hub. All axles are cr-mo. Lastly, there are no
backwards compatibility for the latest hubs except for some parts.
We’ve tried to keep backwards compatibility for the past 20 years but
huge improvements with the latest hub unfortunately didn’t allow us to
do so.