Saji vs Nipponji nibs; what's really the difference?

 I've always thought there were x3 nibs, the big spoon looking Saji nib, the mid sized school-g nib, & the skinny little maru mapping nib.

I was recently watching a Naoki Urasawa video on YouTube where he mentioned discovering the Nipponji nibs after using a Gnib for a long time 

I looked it up & found that the key hole cutout from the Saji differed from the cutout on the Nipponji, which closer resembles the Gnib cutout. I also found that where the Saji has a perfectly curved bowl shape, the Nipponji seems to have very specific bends, namely down the center line to the tip, & on the sides similar to a paper airplane.

I had to know for myself what the deal was since there's absolutely no comparison information about these anywhere online.

What did i find? Well you just saw for yourself, there's pretty much no difference.

By feel alone, the Saji is stiffer, therefore fine lines come with slightly less effort. The Nikko Nipponji feels a breath stiffer than the Tachikawa Nipponji. 

The Saji seems to be capable of slightly thicker maximum line thickness, though it takes more pressure to reach the maximum vs both Nipponji. 

The Saji also seems to allow ink to run more freely, which has pros & cons. This may be ideal with thicker inks, but could be tragic with thinner inks.

If I had to pick one (I did actually, since I keep x3 nibs holders on my pen carousel, the maru, the g, & now the Nikko Nipponji) it would be the Nikko Nipponji for purely ethereal reasons. I'm keeping them all & will probably use them as spares if I run out of my faves & have to wait extra long for shipping new stock.

Try them for yourself & let me know if you discover a subtle difference I missed.