Who Invented QR Codes?

From a factory line to a global standard

The QR code didn’t originate in a startup—it was born on the shop floor. Between 1992 and 1994, Japanese engineer Masahiro Hara developed it at DENSO (later DENSO WAVE) in response to requests from automakers who needed to track parts faster and more reliably. One-dimensional barcodes weren’t enough: they stored too little data, were hard to read, and workers often had to scan several labels in a row. Hara therefore bet on a two-dimensional grid—a code that can be detected and read from different angles, even when dirty. The first QR code was unveiled to the world in 1994.

Go, a “train moment,” and three corner squares

Hara repeatedly describes two sources of inspiration. The first was the game of go: black and white stones on a grid led him to the idea of storing information both horizontally and vertically at the same time. The second was a view from a train of a building with different window patterns on the upper and lower floors—at that moment he realized the reader would benefit from clear “beacons” in the corners that instantly reveal that it’s a QR code and how it’s oriented. That’s why a QR code has three corner squares (finder patterns), whose widths are based on the rarest black-to-white ratio found in print: 1 : 1 : 3 : 1 : 1.

How a QR code works—and why it could, in theory, be “read” by hand

A QR code contains several layers of information. The visible corner squares and the timing lines define position and orientation. Short format metadata tells the reader the error-correction level and the mask pattern used. The data bits are then read in a zigzag path, assembled into codewords, and corrected using Reed–Solomon error correction. Thanks to this, the code remains readable even when rotated, tilted, or partially damaged. In theory, if you know the masking rules, the bit-reading map, and the checksums, you could work through the procedure with pencil on paper—it’s difficult, but the principle is publicly documented and was intentionally designed to be understandable.

How much data fits in a QR code—and why it’s so resilient

Capacity depends on the version and the chosen error-correction level, but the original specification already aimed for high data volume and fast reading. In the highest versions, a QR code can hold roughly seven thousand digits, or thousands of alphanumeric characters, and the manufacturing speed-up also came from the fact that the device can quickly “find” the code in the image without precise aiming. Robust error correction is exactly what enables scanning even when the code is dirty or partially torn.

“He could have been a billionaire,” but Masahiro Hara left QR to the world royalty-free

DENSO WAVE did file several patents related to the QR code, but to promote widespread adoption it chose not to enforce key claims for the standardized QR code and published the specification openly. That means anyone can use QR codes without licensing fees as long as they follow the JIS/ISO standards. The name “QR Code” itself is a registered trademark. This “open” approach is why QR codes so quickly became global infrastructure—Hara didn’t personally get rich from them, but the technology became practically ubiquitous.

Still at the same company—calmly, quietly

Hara still works at DENSO WAVE (as a chief engineer) and focuses on further code development—from security extensions to healthcare use cases, where a code might carry, for example, a person’s basic medical records. In interviews, it’s often noted that he got the decisive idea on a train; media reports also sometimes claim he routinely commutes by train. Hara, however, mainly emphasizes the code’s practicality and openness, and the fact that even after decades he’s stayed with the same work—because some people like to change the world quietly, not through headlines.

Video: A short profile of the QR code inventors (European Patent Office)

An official mini-report about the team behind QR.

Video: I built a QR code “by hand” to show how it works (educational)

A nice visualization of QR code layers and the reading principle.

Sources

1. DENSO WAVE – QR Code development story (Technologies): development background, reading principles, opening up the specification. https://www.denso-wave.com/en/technology/vol1.html (denso-wave.com)
2. DENSO WAVE – About the patent: patent policy and free use for the standardized QR code. https://www.qrcode.com/en/patent.html (QRCode)
3. Unsung Science – The Man Who Invented QR Codes (transcript of an interview with M. Hara): the game of go, the “train moment,” Hara still works at Denso/DENSO WAVE. https://www.unsungscience.com/index.php/2023/07/07/the-man-who-invented-qr-codes/ (unsungscience.com)
4. DENSO – Believing in a Faint Light: Obstacles QR Code developer overcame…: 30th anniversary, interview with Hara; recollection of the idea while looking out from a train. https://www.denso.com/global/en/driven-base/career-life/qr-hara_2408/ (denso.com)