Isometric 500
Model ISO-500
Price history
Not enough dated pre-owned sales yet for a price chart — our threshold is 3. 2 verified sales on record so far.
2 verified transactions on record · USD · methodology
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Isometric 500: the 1992 racquet that brought Yonex’s square head to badminton
The first square head
Yonex lists the Isometric 500 as the first badminton racquet with an isometric head. Isometric is Yonex’s name for a squared-off frame that evens out the lengths of the main and cross strings. The company had introduced the shape in tennis in 1980, with the R-1, R-2 and R-3, and the Isometric 500 carried it into badminton in 1992. Yonex now calls isometric a world standard, used on most badminton racquets. Its own history is candid about the start: players unused to a square racquet did not take to it at once, and the shape spread as the larger sweet area proved itself.
Thirty-two percent, upward
Yonex introduced the racquet as a new product in the September 1992 issue of Japan’s Badminton Magazine, under the headline “New-shape Isometric: badminton gets even more amazing.” The ad explained that equal string lengths removed the “dead space” of a round frame and spread the sweet spot into a large square. Its centerpiece was a “32% UP” badge, and the claim was specific. Because a racquet travels fastest near its tip, Yonex said, the sweet spot had grown 32% upward, giving faster, steeper smashes and steadier receives. Later retail copy turned this into a 32% larger hitting area, which is not what the ad said. Yonex listed a titanium graphite frame, a super-slim carbon shaft and a full racquet case, at ¥21,000 before tax. The company traces the idea to tennis, where Billie Jean King asked it for a larger sweet area without losing a sharp swing.
No named players
No documented Yonex source, press report or tournament record names a professional who used the Isometric 500. Yonex’s anniversary timeline attaches players to later landmarks such as the Ti10 and the Muscle Power 100, but none to this one, and the launch ad sells the shape rather than an endorser. What is documented is Yonex’s standing that year. Badminton made its debut as a full Olympic sport at Barcelona in 1992, and Yonex shuttlecocks, courts and nets were the official equipment.
Navy, then a family
The launch ad shows a navy frame with “SQUARE SPOT” lettered along the head and “ISOMETRIC 500” and “SUPER SLIM CARBON” printed on the shaft. A forum member who bought his in 1992 or 1993 as his first Yonex described it as dark metallic blue with red graphics on the inner frame. No other colorway is documented. Yonex offered two weights: 3U with grip sizes 4 and 5, and 2U with sizes 3 to 5. The shape then spread through the range: Yonex’s 1996 Asian catalog shows six Isometric models, among them the Professional-level Isometric Tour 800 and Power 600; each has its own page. Yonex’s timeline follows with the hollow, one-piece Super Isometric 10 “razor frame” in 1996 and the Isometric Swing Power 900 in 1998, and Yonex Japan’s 2000 and 2001 lists include the Isometric 400 Long and 300 Long, all-carbon Long frames documented only in Japan; each has its own page. The Isometric Swing Power 500 (ISOS500) on those lists is a different, later racquet, documented in 1999–2000; it has its own page.
Few sales, no end date
Verified sales of the Isometric 500 are few so far, all pre-owned and all from Asia resale; the price panel above lists them. When production ended is not documented. The racquet appears in none of Yonex Japan’s archived 2000 and 2001 product and old-model lists, the earliest full lists that survive online, so it was out of the range by then, but no source gives a year. Yonex published no production figures.
Nothing documented to copy
No counterfeit Isometric 500 has been documented, and the fake-spotting guides that circulated from the mid-2000s dealt with newer models. The confusion that does occur is in names. Listings for other Isometric models, and especially for the Isometric Swing Power 500, can turn up under searches for this one.
Where the landmarks begin
Yonex says isometric has been used by the world’s top players since 1992 and is still being developed. Its 2017 anniversary site starts a line of thirteen landmark frames with the Isometric 500, running through the Ti10, Armortec 700 and Nanospeed 7000 to the Duora Z-Strike. Yonex also argues that the larger sweet area let players strike the shuttle higher on the frame, where the head moves fastest, and so influenced how the game developed.
Start with the head: it should be squared off, not oval. Compare the printing with Yonex’s launch ad, which shows “ISOMETRIC 500” and “SUPER SLIM CARBON” on the shaft and “SQUARE SPOT” lettered along the navy frame; one owner describes the finish as dark metallic blue with red graphics on the inner frame. Yonex offered 3U (grips 4–5) and 2U (grips 3–5), so a 4U example does not match the launch specifications. The ad names no country of manufacture, so a made-in marking is a detail to note, not proof either way. Make sure the listing is not an Isometric Swing Power 500, a different and later model. On a frame this old, check the head and the joint for cracks before stringing it.
The Isometric 500’s appeal is historical: Yonex’s first isometric badminton racquet and the start of its anniversary timeline. Buy on the details that can be checked, the head shape, the navy finish and the printed name, and don’t pay for professional provenance, since none is documented.
Verified prices last updated Jul 2026. All data based on tracked secondary market transactions.