"Lisa's Sax" is the third episode of the ninth season of the American animated television series The Simpsons. It originally aired on Fox in the United States on October 19, 1997, to overwhelmingly positive reviews. In the series' sixth flashback episode, it is explained how Lisa got her saxophone. The episode was executive produced by Al Jean and Mike Reiss and was the first episode Jean wrote by himself, as all of his previous writing credits had been shared with Reiss. It was directed by Dominic Polcino and guest starred Fyvush Finkel, who appeared as himself portraying Krusty in a film. The episode was written with a small staff that consisted of Jean, Reiss and David Stern, among others. According to Reiss, the final episode contained 80–90% of Jean's original script. It is the sixth flashback episode done by the show. "The Way We Was" was the first flashback episode and in it, Homer graduated from high school in 1974 and that made it difficult to have a realistic timeframe as this episode is set in 1990. This is the last episode in which Doris Grau has a speaking role as Lunchlady Doris, although this episode aired nearly two years after her death. It would also mark the final time the character would speak until Season 18's "The Mook, the Chef, the Wife and Her Homer" when she was voiced by Tress MacNeille.
Cultural references
The opening scene of the episode depicts a TV movie broadcast by The WB titled The Krusty the Klown Story: Booze, Drugs, Guns, Lies, Blackmail and Laughter; although this is a parody of cheesy TV movie biopics in general, it more specifically lampoons Love and Betrayal: The Mia Farrow Story which aired on Fox in 1995. While telling Bart and Lisa about 1990, Homer says, "Tracey Ullman was entertaining America with [...] crudely drawn filler material." This is a reference to The Simpsonss debut as "bumpers" airing before and after commercials on The Tracey Ullman Show. At the end of the episode, Lisa performs a brief, cruder rendition of the hook of "Baker Street" by Gerry Rafferty on her new saxophone before the music segues into the original song. The authors of the book I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide, Warren Martyn and Adrian Wood, called it "a terrific episode, full of amusing self-referential wit and it is especially nice to finally discover what it was that caused Bart to go down the path to the dark side." A review of The Simpsons season 9 DVD release in The San Diego Union-Tribune highlighted "Lisa's Sax" along with "All Singing, All Dancing" and "Trash of the Titans" as some of the more memorable episodes of the series.
Stephen Becker of The Dallas Morning News noted that season 9 "has a special affinity for Lisa", and highlighted this episode along with "Das Bus" and "Lisa the Simpson" in his review of the DVD. A segment of the episode where two schoolgirls chant the digits of pi while playing patty-cake is used by mathematicians Sarah J. Greenwald of Appalachian State University and Andrew Nestler of Santa Monica College in a website on the mathematics of The Simpsons.