Betamax was a 1/2-inch home video tape recording format engineered by Sony. It was derived from the earlier professional 3/4-inch U-matic video cassette format. Unlike VHS, it had no guard band, and used recording azimuth to reduce cross-talk. Some say the name "Betamax" was derived from a Japanese phrase (beta raw + gaki write). However, the system's trademark punningly incorporated the Greek letter &beta. It was also called Beta or Betacord.

Compared with VHS, the size of the cassette is smaller and is widely said to have a better picture quality than VHS. Other advantages included a straighter path for the tape though the machinery, making it start up much faster after inserting the cassette, and transitioning from play to fast forward or rewind faster as well. This also led to somewhat less wear on the tape itself, and therefore somewhat longer cassette lifetime.

For home use Betamax lost over VHS despite a huge marketing push by Sony. In his autobiography, Sony founder Akio Morita attributes this to Sony's refusal to license the format, allowing the technically inferior VHS format to get "critical mass". Others believe that the shorter recording time of Betamax was the factor that retarded its early consumer adoption, a problem that led Sony into a race in the 1980s to increase the capacity of the format, one they never were ahead in for very long.

Once VHS had achieved a critical mass in terms of the installed base of home video recorders, the rest of the Betamax marketing chain collapsed. Eventually, Sony started producing its own VHS format recorders, effectively conceding the "format war". The last American model appeared on the market in 1993, and overseas production of Betamax VCRs had completely halted by 1998. Sony continued manufacturing a limited number of Betamax VCRs for the Japanese market until 2002, when they officially announced the end of the Betamax consumer line.

The process by which VHS won over the apparently superior Betamax format has become a classic case study in marketing, to the point of the creation of a nounal verb "to Betamax" where a proprietory technology format overwhelmed in the market by another format allowing multiple competing licensed manufacturers, as in "Microsoft Betamaxed Apple out of the PC market".

Surprisingly it appears Sony never learned the Betamax lesson themselves, and have repeatedly attempted to introduce similar technologies with similarily limited appeal. For instance, it appears that the recent Memory Stick system offers no technical advantages at all over the almost identical MMC system, yet Sony continues to advertize Memory Stick and offer it as the only removable media standard on their own consumer electronics and computers.

Technologies such as Betacam evolved from the Beta format and became the most widely used professional recording format by television stations until it was surpassed by digital media at the end of the 1990s. The Jerry Springer Show records all shows on Betacam.

One other major result of the introduction of the Betamax technology was a lawsuit, Sony Corp. v. Universal City Studios, which went all the way to the U.S. Supreme Court before the legality of home videotaping was finally determined. The court judgement held that home videotape recorders were a legal technology since they had "substantial non-infringing uses".

A 1999 anime series which is extremely popular in Japan and the United States, Cowboy Bebop, in one of its episodes features a scene in which some of the characters acquire an antique vidocassette and undertake an arduous journey to find a working machine to play it on. Unfortunately their efforts are undermined by their technical and historical ignorance, because the tape is VHS and the machine is Betamax.

See also: video cassette recorder, VHS, network externality, whole product, tipping point

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