What a fascinating story! Thank you for sharing! What you’re referring to is probably takuan (たくあん）, pickled yellow daikon 🌞 The yellow color is traditionally from a long fermenting process, but nowadays if you buy it at a major supermarket it can be added food dye.
I usually buy my takuan in Japan, but here’s a pretty simple and traditional recipe if you’d like: https://translate.google.com/translate?sl=ja&tl=en&u=https%3A%2F%2Fwww.recipe-blog.jp%2Fprofile%2F38406%2Frecipe%2F364865
The recipe is in Japanese but it translates into English pretty well! Also, the recipe Steve Stehr seems pretty good too 😊 I'll have to see if I can get a recipe on easy homemade sukiyaki out soon then...
Let me know how it goes, and if you have any questions feel free to email me at firstname.lastname@example.org!