California Roll has became the iconic Sushi item in US and rest of the world. As far as I know (based on the restaurants I worked for,) it is the most popular item on the menu. Even at stores like Whole Foods and Trader Joe's, it is the most visible sushi item. So, who invented California Roll and how did it become so popular? The story I heard (and was telling people) was that one day, a sushi chef at sushi bar in Los Angeles (little Tokyo) was asked the special of the day by a regular customer. Since the chef had no special on that day, after thinking for a while, he added avocado, which was "unusual" item at that time, to crab hand roll. The customer liked it so much that it became a regular item on the menu. In finding out, it turned out that the story I knew was wrong. It appears now there are two stories (or inventors) for California Roll. Story #1 The most popular story goes to Ichiro Mashita of Tokyo Kaikai in Little Tokyo, Los Angeles, circa 1970. It is said that Mr. Mashita substituted avocado in place of toro for its rich oily flavor. Traditional Japanese roll is seaweed out and Americans disliked the taste of chewing and texture of nori seaweed, which led to the invention of "Uramaki," inside-out roll. How did Mr. Mashita think of adding avocado? Another story says that one of his regulars asked him to make sushi for Caucasians. At that time, most Americans never heard of sushi, let alone eat raw fish. So, Mr. Mashita thought of Avocado for its low cost and never ending abundant year supply. Story #2 Now this came as a shocker to many sushi fans.
This second story came out in 2012. Here in this article by The Globe and Mail, a Canadian Sushi Chef (well, he actually is Japanese living in Canada), Hidekazu Tojo claimed HE is the inventor of California Roll.
According to Mr. Tojo, he thought of using crab for sushi because fresh fish suitable for sushi was unavailable in Vancouver when he arrived in 1971.
Also, most Westerners disliked eating seaweed, so, he made inside-out roll to hide the flavor. Though against the Japanese tradition of seaweed out roll, many of his customers liked it.
Many of Mr. Tojo's customers were from Los Angeles. They loved his crab and avocado roll, hence the name California Roll.
I do have to mention that I came across several other stories and inventors of California Roll.
For now, Mr. Mashita's story appears to be the most credible.
Then again, I also learned that though Hanaya Yohei is credited to be the inventor of Nigiri Sushi, it also appears that there are many other "true" inventor of Nigiri Sushi.