#Ajishio 味塩 アジシオ or "flavor salt" is a commercial product made by #Ajinomoto, a mix of sodium chloride (table salt) and monosodium glutamate (MSG), in a ratio of 7 parts salt to 1 part MSG. It's not commonly sold in the US, but you may find it at Asian specialty markets, or you can make your own.

I make my own using iodized salt and Ajinomoto's "Hi-Mi" ハイミー (short for "high umami"), which is 95% MSG and 5% ribonucleotides (sodium inosinate and sodium guanylate), for even more #umami.