I've been doing a math course and occasionally think of picking up these analogue tools. Someone on Hacker News had me interested in the Soroban, the Japanese abacus [1], which is still used to train insane mental math speeds to this day [2].
We're definitely on a similar wavelength. I actually own a couple Japanese abaci and know the basics. Top performers feel near magical: double-fisters[0] and blazingly fast mental arithmetic [1].
Have you used it much? I'd like one, but I can imagine it sitting on my desk for years unused. I have "Secrets of Mental Math" by Arthur Benjamin and have wanted to practice some of those mental math skills, and I wonder if learning the soroban will interfere with my existing mental calculation framework (which is admittedly weak at the moment).
[0]:https://www.youtube.com/watch?v=EK6uIjjkrGE
[1]:https://youtu.be/-kjUCtqSWlw?feature=shared&t=451