kennethreitz
ce93f429a2
Publish the Obsidian vault's Knowledge folder as /knowledge (881 notes, 67 folders), with a Knowledge item in the nav and footer. - scripts/import_knowledge.py regenerates data/knowledge from the vault: slugged paths, folder notes as index pages, wikilinks resolved to site links (or plain text), callouts, highlights, and Dataview tables rendered statically. Personal notes are withheld via an exclusion list plus a privacy guard. - tuftecms/core/knowledge.py builds a concept index from note titles and aliases. First mentions on ordinary pages link to their Knowledge note (capped, never in headings, code, links, or sidenotes); Knowledge pages list related notes and where they're mentioned across the site; other pages get a Related Knowledge block. - Knowledge URLs join sitemap.xml (so the sweep test covers them), never displace existing legacy slugs, list alphabetically, and mermaid diagrams render client-side only on pages that have them.
2.3 KiB
description, source
| description | source |
|---|---|
| Twelve bars wide, and deep enough to fall into. | obsidian-knowledge |
Twelve-Bar Blues
Twelve bars wide, and deep enough to fall into.
The Progression
The twelve-bar blues is less a chord progression than a form — a repeating twelve-measure frame built from the three primary chords of a key. The most common shape gives four bars of the tonic, two of the subdominant, two more of the tonic, then a turnaround through the dominant and back. Over this scaffold the melody, the lyric, and the improvised solo unfold in a call-and-response arc: a line, its repetition, and a resolving answer.
Its emotional charge comes from the dominant sevenths. Blues players typically color all three chords as sevenths, so even the "home" tonic carries the restless bite of a flatted seventh. The tension never fully dissolves — it just cycles, which mirrors the form's lyrical logic of stating a trouble, restating it, and answering it. The predictable frame is exactly what frees the soloist to roam.
Structure
| Attribute | Value |
|---|---|
| Roman numerals | I–I–I–I / IV–IV–I–I / V–IV–I–V |
| Example in C | C7 (×4) / F7 – F7 – C7 – C7 / G7 – F7 – C7 – G7 |
| Chords used | Dominant Seventh (I, IV, V) |
| Character | Earthy, cyclical, expressive |
| Function | 12-bar frame: tonic → subdominant → dominant turnaround |
In Practice
It is the foundation of blues and the direct ancestor of rock and roll — "Sweet Home Chicago," "Johnny B. Goode," "Hound Dog," and "Rock Around the Clock" all ride the twelve-bar frame. Countless variations exist, from the quick-change (moving to IV in bar two) to jazz-blues reharmonizations that lace ii-V-I cadences into the turnaround. At heart it remains the I-IV-V stretched across twelve measures.