I have been playing with HIFI, toys, Yonex badminton gears and cars from Japan for 30 years.
Seriously speaking, if you open a Japanese domestic version of most Things to compare with export products, consistently you could find higher quality parts put inside the domestic equipment.
Just quote one example: In Around 1990, We did side by side open up an export version and a domestic Japanese version Pioneer pd-901 CD player! The domestic version use much better parts such as 'Elna cap for audio'but the export version use mass marker caps. Although both players were made in Japan, the cost for building the players were different.
So if I wanna compare national and Panasonic, you would like to open up both boxes and take a lurk. we can see if there's quality difference between the parts use, the size of the transformers, size of magnets etc.