Aztec Rune

Overview

An Aztec Rune is a tiny, fixed-size machine-readable mark — 11 × 11 modules — designed on the basis of the Aztec Code specification but carrying only a single small value [2]. Each rune encodes a number in the range 0 to 255 (one byte, or up to 3 decimal digits), giving exactly 256 possible runes [2, 3]. It is defined in Annex A of ISO/IEC 24778, the international Aztec Code standard, and reuses the core symbol of the compact version of aztec Code while replacing the variable data structure with a fixed 8-bit message [2]. Runes are intended for situations where the payload can be reduced to a handful of values and the mark must be as small as possible.

History

The aztec Code was invented by Andrew Longacre, Jr. and Robert Hussey in 1995 and published by AIM, Inc. in 1997; the patent was released into the public domain, making the symbology free to implement [4]. The Aztec Rune was specified as part of the same family and is included as Annex A of the ISO/IEC standard ISO/IEC 24778:2008, Information technology — Automatic identification and data capture techniques — Aztec Code bar code symbology specification [1, 2]. As an annex to the main Aztec Code standard, the rune shares the symbology's finder pattern and error-correction machinery rather than being a separate code [2].

Technical specification

Fixed geometry. Every Aztec Rune is 11 × 11 modules, the same footprint as the smallest (compact) aztec symbol, with no size variation [2, 3].

Capacity. A rune encodes a single integer 0–255 — one byte, or up to 3 digits [2, 3]. There are therefore exactly 256 distinct runes.

Structure. A rune is built from the core of the compact aztec Code: a central bull's-eye finder pattern of alternating black and white concentric rings, orientation markers at the corners, and a single data layer carrying the 8-bit message with Reed–Solomon error correction [2, 3].

No mode message. Unlike a full aztec symbol, a rune omits the variable mode message that normally surrounds the bull's-eye to describe the symbol's size and data-layer count; the rune's geometry is fixed, so this descriptor is unnecessary [2]. Furthermore, the rune's data bits are arranged to be numerically distinct from a normal Aztec symbol, so a rune cannot be mistaken for (and will not falsely decode as) an ordinary Aztec Code, and vice versa [2, 3].

Error resilience. Even at this minimal size, the Reed–Solomon coding gives the rune damage resistance and data recovery [2].

Use cases

• Augmented reality object tracking — the small, distinctive rune acts as a fiducial/marker whose value identifies the tracked object [2, 3].
• Marking very small items, where there is not enough physical space for a full barcode or QR/Aztec symbol [2, 3].
• Compact tagging of fixtures, samples, or assets that only need an 8-bit identifier [2].

Implementations

• zint (C, 771★, active 2026) — open-source library supporting aztec Code and Aztec Runes [5].
• delimitry/aztec_code_generator (Python, 25★, last active 2024) — pure-Python Aztec Code generator.
• dlenski/aztec_code_generator (Python, 11★, active 2026) — maintained fork with ZXing-compatibility fixes.
• BWIPP (postscriptbarcode) — exposes a dedicated aztecrune encoder that takes a value 0–255 [3].

Comparison

Feature	Aztec Rune	Full / compact aztec Code
Size	Fixed 11 × 11 modules	15 × 15 up to 151 × 151 (compact: 15–27)
Capacity	0–255 (1 byte / 3 digits)	Up to ~3000 characters
Mode message	None (fixed geometry)	Present (encodes size + layers)
Finder	Bull's-eye	Bull's-eye
Error correction	Reed–Solomon	Reed–Solomon (user-selectable %)
Distinctness	Numerically distinct from data symbols	—

The Aztec Rune is essentially aztec Code stripped to its smallest meaningful form: it keeps the bull's-eye finder and Reed–Solomon protection but drops the mode message and variable data layers, trading capacity for a guaranteed minimal footprint and a guarantee that it won't collide with normal Aztec symbols [2, 3].

Fun facts

• There are exactly 256 possible Aztec Runes — the full set fits on a single reference chart, one per byte value [2, 3].
• The rune's bit layout is deliberately engineered so a rune and a real aztec data symbol are mutually unmistakable, preventing cross-decoding in mixed environments [2].

Status

The Aztec Rune is a current, standardized part of ISO/IEC 24778 (Annex A) and is supported by mainstream open-source and commercial barcode toolkits [1, 2, 5].

Sources

1 ISO/IEC 24778:2008 — Aztec Code bar code symbology specification — ISO, 2008 2 Aztec Code Rune — Aspose Documentation 3 Aztec Runes — BWIPP wiki 4 Aztec Code — Wikipedia — Wikipedia 5 zint/zint — GitHub, 2026

Deployments

No country reports mention this standard by name.

Regions / aggregations not mapped to a single country

• Universal