feat(kb): intermediate progressions + level tags for jazz, gospel, rnb (task P-20)

6 new level:'intermediate' progressions (tritone sub, rhythm-changes
bridge, gospel passing-dim walk-up, tonicized amen w/ borrowed iv,
Just-the-Two-of-Us loop, Sir Duke chromatic vi) x 2 guitar plays each;
all progressions in the three styles now carry explicit level. KB:
56 progressions / 112 plays. Critic returned once (3 caption theory
misstatements), fixed, PASS on re-gate (voice-leading arithmetic
hand-verified from shape constants).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/data/kb/gospel/guitar.js

@@ -32,9 +32,12 @@ const SUS4_6 = { rootStr: 6, offsets: [0, 0, 'x', 'x', 0, 'x'], fingers: [1, 2,
 const MAJ_6 = { rootStr: 6, offsets: [0, 2, 2, 1, 'x', 'x'], fingers: [1, 3, 4, 2, 0, 0] }       // R–5–R–3 (E-shape)
 const MAJ_5 = { rootStr: 5, offsets: ['x', 0, 2, 2, 2, 'x'], fingers: [0, 1, 2, 3, 4, 0] }       // R–5–R–3 (A-shape)
 
-// --- the passing diminished 7th (#iv°7) ---
+// --- the passing diminished 7th (#iv°7 / ♯i°7 — symmetric, one grip fits both) ---
 const DIM7_5 = { rootStr: 5, offsets: ['x', 0, 1, -1, 1, 'x'], fingers: [0, 2, 3, 1, 4, 0] }     // R–♭5–𝄫7–♭3 (symmetric)
 
+// --- the borrowed iv (minor 6th on the middle strings, for the tonicized Amen) ---
+const MIN6_4 = { rootStr: 4, offsets: ['x', 'x', 0, -2, 0, -2], fingers: [0, 0, 3, 1, 4, 2] }    // R–♭3–6–R
+
 export default {
   styleIntro:
     'Gospel guitar lives between the organ and the choir: short, voice-led grips that comp the changes without crowding the keys. The signature sounds are guide-tone shells for the moving 2–5–1 chains, 9th and add9 colour on the resting chords, sus tension in the modern praise vamp, and a single passing diminished that makes a plain hymn sound like church. Keep the fifth and often the root to the bass — your job is the 3rds, 7ths, and the colour note.',
@@ -188,6 +191,58 @@ export default {
         tips: 'The two min9 chords are the identical shape a fourth apart — one of the easiest gospel moves to internalize. The maj9 resolution sounds especially plush after a back-door dominant.',
       },
     ],
+
+    'gospel-walkup-dim': [
+      {
+        label: 'Walk-up on the A string (shells)',
+        level: 'intermediate',
+        chords: [
+          { shape: SHELL_5.maj7, note: 'Imaj7 — root on the A string' },
+          { shape: DIM7_5, note: '♯i°7 — one fret up: the ladder rung' },
+          { shape: SHELL_5.min7, note: 'ii7 — one more fret: the bass arrived by half steps' },
+          { shape: SHELL_6.dom7, note: 'V7 — turn around and climb again' },
+        ],
+        tips: 'The first three roots sit on one string, one fret apart — the walk-up is literally visible under your hand. Give the diminished its full beat but keep it quieter than the chords around it: it is a passing chord, a rung, not a destination. Over it, arpeggiate its four notes (all minor 3rds apart) — the fastest route from I\'s tones to ii\'s.',
+      },
+      {
+        label: '9th-coloured walk-up (mixed registers)',
+        level: 'intermediate',
+        chords: [
+          { shape: MAJ9_6, extensions: ['9'], note: 'Imaj9 — low root, the 9 shining on top' },
+          { shape: DIM7_5, note: '♯i°7 — the diminished stays plain; its tension IS the colour' },
+          { shape: MIN9_5, extensions: ['9'], note: 'ii9' },
+          { shape: DOM9_5, extensions: ['9'], note: 'V9' },
+        ],
+        tips: 'Same climb with the gospel shimmer on the resting chords. Remember what the ♯i°7 really is — a rootless VI7♭9 aimed at ii — but not every note climbs: only the root rises a half step into ii\'s root, while the hidden dominant\'s ♭7 and ♭9 sigh downward into the ii9. Don\'t decorate the diminished; decorate its resolution.',
+      },
+    ],
+
+    'gospel-tonicized-amen': [
+      {
+        label: 'Shell tag — one finger tells the story',
+        level: 'intermediate',
+        chords: [
+          { shape: SHELL_6.maj7, note: 'Imaj7 — R–7–3' },
+          { shape: SHELL_6.dom7, note: 'I7 — same grip, one finger drops a fret: the 7 falls to ♭7' },
+          { shape: SHELL_5.maj7, note: 'IVmaj7 — same fret, root string up (the I7 pointed here)' },
+          { shape: MIN6_4, note: 'iv6 — the borrowed minor on the middle strings' },
+          { shape: SHELL_6.maj7, note: 'Imaj7 — home' },
+        ],
+        tips: 'Watch the two half-step falls: the I\'s major 7 drops to ♭7 (turning I into V7/IV), then the IV\'s 3rd drops to ♭3 (the borrowed iv). Everything else holds. When soloing, target exactly those two falling voices — the ♭7 of I7 resolves into the 3rd of IV, and the iv\'s ♭3 sighs down to the 9/1 of home.',
+      },
+      {
+        label: '9th-coloured tag (upper register)',
+        level: 'intermediate',
+        chords: [
+          { shape: MAJ9_6, extensions: ['9'], note: 'Imaj9' },
+          { shape: DOM9_6, extensions: ['9'], note: 'I9 — the same one-finger drop, with the 9 held on top' },
+          { shape: MAJ9_6, extensions: ['9'], note: 'IVmaj9 — identical grip five frets up' },
+          { shape: MIN6_4, note: 'iv6 — drop to the plain borrowed minor; no 9 here' },
+          { shape: MAJ9_6, extensions: ['9'], note: 'Imaj9 — resolve with colour' },
+        ],
+        tips: 'The maj9 → dom9 move is the same story as the shells — only the D-string finger moves, 7 falling to ♭7 — but the held 9 makes the tag glow. Leave the iv6 uncoloured: after four 9th chords, the bare borrowed minor is the emotional dip that sets up the resolution.',
+      },
+    ],
   },
 
   improv: {

src/data/kb/gospel/progressions.js

@@ -5,6 +5,13 @@
 //   Wikipedia: Plagal cadence, Backdoor progression.
 // Song references are kept honest: where a single definitive recording isn't
 // certain, the move is described by its standard use in the tradition.
+//
+// Level tags + the two intermediate progressions added by task P-20.
+// Walk-up/tag theory verified against: hearandplay.com ("Little known ways to
+// use diminished walk-ups and walk-downs", "An In-Depth Breakdown Of The
+// Classic 1-4 Walk-Up"), pianogroove.com (Gospel Walk-Ups; Gospel Passing
+// Chords & Substitutions), docs/progression-repertoire.md §1 (I–♯i°–ii,
+// I–I7–IV, IV–iv–I rows).
 export default [
   {
     id: 'gospel-cycle-251',
@@ -16,6 +23,7 @@ export default [
     mode: 'major',
     songs: ['traditional gospel turnaround', 'His Eye Is on the Sparrow (reharmonized)'],
     tip: 'Every root falls a fifth and the off-diatonic VI7 pushes hard to ii — chain two ii–V cells back to back and the ear is dragged home. Voice-lead the 3rds and 7ths and your hand barely moves.',
+    level: 'intermediate',
   },
   {
     id: 'gospel-amen-625',
@@ -27,6 +35,7 @@ export default [
     mode: 'major',
     songs: ['traditional hymn endings', "I'll Fly Away (turnaround/tag)"],
     tip: 'The 6–2–5–1 is the gospel turnaround — the extended cousin of the 2–5–1 that returns you from chorus to verse. Tag it with the plagal IV–I "Amen" for the classic church ending.',
+    level: 'foundation',
   },
   {
     id: 'gospel-iv-passing-dim',
@@ -38,6 +47,7 @@ export default [
     mode: 'major',
     songs: ['gospel hymn reharmonization', 'Amazing Grace (passing-chord arrangement)'],
     tip: 'The #iv°7 is a chromatic passing chord linking IV back to I (bass walks 4 → #4 → 5/1). It is almost a signature of the gospel sound — one borrowed diminished and a plain hymn turns into church.',
+    level: 'intermediate',
   },
   {
     id: 'gospel-sus-vamp',
@@ -49,6 +59,7 @@ export default [
     mode: 'major',
     songs: ['Every Praise — Hezekiah Walker (vamp feel)', 'contemporary gospel/CCM praise loop'],
     tip: 'Contemporary gospel leans on open sus and add9 colour instead of plain triads — the suspended 4th over V never fully resolves, keeping the vamp hovering and "lifting". Loop it; the tension is the point.',
+    level: 'foundation',
   },
   {
     id: 'gospel-backdoor',
@@ -60,5 +71,30 @@ export default [
     mode: 'major',
     songs: ['gospel/soul turnaround', 'standard back-door cadence (e.g. Tenderly, bars 5–7)'],
     tip: 'iii→vi is a soft diatonic drop; the ♭VII7 is the "back door" — a borrowed dominant a whole step below I that resolves up by step instead of down a fifth. A warmer, less expected way home than V7.',
+    level: 'intermediate',
+  },
+  {
+    id: 'gospel-walkup-dim',
+    name: 'Chromatic walk-up (I–♯i°7–ii7–V7)',
+    rn: ['Imaj7', '♯i°7', 'ii7', 'V7'],
+    degrees: [0, 1, 2, 7],
+    qualities: ['maj7', 'dim7', 'min7', 'dom7'],
+    bars: [1, 1, 1, 1],
+    mode: 'major',
+    songs: ['traditional gospel walk-up (bass climbs 1–♯1–2)', 'the standard hymn-to-church reharmonization move'],
+    tip: 'The ♯i°7 turns the step from I to ii into two half-steps — the bass climbs while the upper voices barely move. It works because ♯i°7 is a rootless VI7♭9, the secondary dominant of ii in disguise; then the V7 launches the loop again.',
+    level: 'intermediate',
+  },
+  {
+    id: 'gospel-tonicized-amen',
+    name: 'Tonicized Amen (I–I7–IV–iv–I)',
+    rn: ['Imaj7', 'I7', 'IVmaj7', 'iv6', 'Imaj7'],
+    degrees: [0, 0, 5, 5, 0],
+    qualities: ['maj7', 'dom7', 'maj7', 'min6', 'maj7'],
+    bars: [1, 1, 1, 1, 2],
+    mode: 'major',
+    songs: ['Amazing Grace ("how sweet the sound" — the I7 pointing at IV)', 'traditional hymn tag (Amen with the borrowed iv)'],
+    tip: 'Two borrowed notes tell the whole story: the ♭7 that turns I into the dominant of IV (a secondary dominant, V7/IV), and the ♭3 that turns IV minor on the way home. Both fall by half step — the gospel tag is a pair of sighs.',
+    level: 'intermediate',
   },
 ]

src/data/kb/jazz/guitar.js

@@ -146,6 +146,54 @@ export default {
       },
     ],
 
+    'jazz-tritone-sub': [
+      {
+        label: 'Shells down one string (chromatic slide)',
+        level: 'intermediate',
+        chords: [
+          { shape: SHELL_5.min7, note: 'ii7 — root on the A string' },
+          { shape: SHELL_5.dom7, note: '♭II7 — two fingers drop a fret; the guide-tone finger stays put' },
+          { shape: SHELL_5.maj7, note: 'Imaj7 — one more fret down: home' },
+        ],
+        tips: 'The tritone sub turns the ii–V–I bass into a one-string chromatic slide: 2 → ♭2 → 1, one fret per chord. It works because ♭II7 and V7 share their guide tones — the 3rd and ♭7 swap names (in C: Db7 has F and B, exactly G7\'s B and F). Target the ♭II7\'s 3rd when soloing; it is the old V7\'s ♭7.',
+      },
+      {
+        label: 'Drop-2 slide, top four strings',
+        level: 'intermediate',
+        chords: [
+          { shape: DROP2.min7Root, note: 'ii7 — root position, root on the D string' },
+          { shape: DROP2.dom7Root, note: '♭II7 — same architecture, one fret down' },
+          { shape: DROP2.maj7Root, note: 'Imaj7 — one more fret down: three voices fall a half step, one holds' },
+        ],
+        tips: 'The upper-register version: three root-position drop-2 grips, roots falling a fret at a time. Each change is three voices dropping a half step around one common tone — the ii7\'s ♭3 is held to become the ♭II7\'s 3rd, then the ♭II7\'s ♭7 is held to become the Imaj7\'s 7. High and thin, it stays out of the piano\'s way, and the top string sings the guide-tone line: held into the ♭II7, falling a half step into home.',
+      },
+    ],
+
+    'jazz-rhythm-bridge': [
+      {
+        label: 'Shells around the circle',
+        level: 'intermediate',
+        chords: [
+          { shape: SHELL_6.dom7, note: 'III7 — V7 of vi, the first domino' },
+          { shape: SHELL_5.dom7, note: 'VI7 — root string up, nearly the same fret' },
+          { shape: SHELL_6.dom7, note: 'II7 — the pattern repeats a whole step down' },
+          { shape: SHELL_5.dom7, note: 'V7 — hands you back the A section' },
+        ],
+        tips: 'One grip pair, four chords: roots falling in fifths alternate 6th → 5th string at almost the same fret, so the whole bridge sits in one position. Each chord is the V of the next — comp two bars each and voice-lead the ♭7 falling a half step onto the next chord\'s 3rd.',
+      },
+      {
+        label: 'Drop-2, alternating inversions (top four strings)',
+        level: 'intermediate',
+        chords: [
+          { shape: DROP2.dom7Inv2, note: 'III7 — 3rd in the bass voice' },
+          { shape: DROP2.dom7Root, note: 'VI7 — nearest root-position grip' },
+          { shape: DROP2.dom7Inv2, note: 'II7 — back to the inversion' },
+          { shape: DROP2.dom7Root, note: 'V7 — root position into the turnaround' },
+        ],
+        tips: 'Alternating the 3rd-in-the-bass grip with root-position drop-2 keeps every change a short hop — root-position-only would force five-fret jumps around this circle. Two bars per chord is room to decorate: restrike on the Charleston, or walk the top voice.',
+      },
+    ],
+
     'jazz-blues': [
       {
         label: 'Shells through the form',

src/data/kb/jazz/progressions.js

@@ -1,3 +1,8 @@
+// Level tags + the two intermediate progressions added by task P-20.
+// Intermediate-entry theory verified against: musictheorymanual.com &
+// learnjazzstandards.com (Girl from Ipanema tritone sub, ii–♭II7–I),
+// pianogroove.com (Ipanema harmony/comping analysis), Wikipedia: Rhythm changes
+// (bridge = III7–VI7–II7–V7 circle of dominants), docs/progression-repertoire.md §1.
 export default [
   {
     id: 'jazz-251-major',
@@ -9,6 +14,7 @@ export default [
     mode: 'major',
     songs: ['All The Things You Are', 'Tune Up — Miles Davis', 'Honeysuckle Rose'],
     tip: 'The 7th of each chord resolves down a half-step to the 3rd of the next — that two-note thread is the whole progression.',
+    level: 'foundation',
   },
   {
     id: 'jazz-251-minor',
@@ -20,6 +26,7 @@ export default [
     mode: 'minor',
     songs: ['Autumn Leaves (bridge)', 'Blue Bossa', 'Beautiful Love'],
     tip: 'Same engine as the major ii–V–I, darker fuel: the ♭5 of the iiø7 is the ♭9 colour waiting to happen on the V7.',
+    level: 'foundation',
   },
   {
     id: 'jazz-rhythm-a',
@@ -31,6 +38,7 @@ export default [
     mode: 'major',
     songs: ['I Got Rhythm — Gershwin', 'Oleo — Sonny Rollins', 'Blue Moon'],
     tip: 'A loop, not a line — bar 4 hands you straight back to bar 1. Learn it as one circular shape your hands repeat.',
+    level: 'foundation',
   },
   {
     id: 'jazz-625',
@@ -42,6 +50,7 @@ export default [
     mode: 'major',
     songs: ['Fly Me to the Moon', 'Autumn Leaves (A section, relative view)'],
     tip: 'Pure circle-of-fifths motion: every root falls a fifth. If you can hear this one, you can predict half the jazz repertoire.',
+    level: 'foundation',
   },
   {
     id: 'jazz-blues',
@@ -53,5 +62,30 @@ export default [
     mode: 'major',
     songs: ["Billie's Bounce — Charlie Parker", "Now's the Time — Charlie Parker", 'Tenor Madness — Sonny Rollins'],
     tip: 'A 12-bar blues wearing a suit: bars 8-10 swap the plain V-IV for a VI7 → ii–V turnaround. Hear bar 8 coming and you sound like a jazz player.',
+    level: 'foundation',
+  },
+  {
+    id: 'jazz-tritone-sub',
+    name: 'Tritone-sub cadence (ii–♭II7–I)',
+    rn: ['ii7', '♭II7', 'Imaj7'],
+    degrees: [2, 1, 0],
+    qualities: ['min7', 'dom7', 'maj7'],
+    bars: [1, 1, 2],
+    mode: 'major',
+    songs: ['The Girl from Ipanema — Jobim (ii–♭II7–I in the A section)', 'standard substitute for any V7 in any tune'],
+    tip: 'The ♭II7 replaces V7 because they share the same tritone — the 3rd and ♭7 simply trade names. What changes is the bass: 2–♭2–1, a chromatic slide instead of a fifth-fall. Your old ii–V line still works over it.',
+    level: 'intermediate',
+  },
+  {
+    id: 'jazz-rhythm-bridge',
+    name: 'Rhythm changes bridge (circle of dominants)',
+    rn: ['III7', 'VI7', 'II7', 'V7'],
+    degrees: [4, 9, 2, 7],
+    qualities: ['dom7', 'dom7', 'dom7', 'dom7'],
+    bars: [2, 2, 2, 2],
+    mode: 'major',
+    songs: ['I Got Rhythm — Gershwin (bridge)', 'Oleo — Sonny Rollins (bridge)', 'Anthropology — Parker/Gillespie (bridge)'],
+    tip: 'Four dominants, each the V of the next — the bridge leaves home and falls back in fifths until it hands you the A section. Follow the ♭7 of each chord dropping a half step onto the 3rd of the next; that chromatic thread is your solo map.',
+    level: 'intermediate',
   },
 ]

src/data/kb/rnb/guitar.js

@@ -169,6 +169,58 @@ export default {
         tips: 'For the gospel walk, insert a passing diminished between any two diatonic chords a step apart (I→♯i°→ii) — same borrowed-from-the-choir logic as the iv.',
       },
     ],
+
+    'rnb-justthetwo': [
+      {
+        label: 'Smooth-soul 9ths and the 13',
+        level: 'intermediate',
+        chords: [
+          { shape: MAJ9_5, extensions: ['9'], note: '♭VImaj9 — the lush opener' },
+          { shape: DOM13_6, extensions: ['13'], note: 'V13 — dominant colour without the bark' },
+          { shape: M9_5, extensions: ['9'], note: 'i9 — home, briefly' },
+          { shape: M9_5, extensions: ['9'], note: '♭vii9 — same grip, two frets down' },
+          { shape: DOM9_5, extensions: ['9'], note: '♭III9 — the V of ♭VI: the loop re-arms itself' },
+        ],
+        tips: 'Treat the last two chords as one gesture — a ii–V pointing at the ♭VImaj9 that starts the next lap (in the original they share a single bar). Solo target: the major 7 of ♭VI is the sweetest note in the loop, and the ♭III9\'s ♭7 falls a half step onto it.',
+      },
+      {
+        label: 'Leaner set with the altered V',
+        level: 'intermediate',
+        chords: [
+          { shape: MAJ7_5, note: '♭VImaj7 — plainer, room for the vocal' },
+          { shape: HENDRIX, extensions: ['#9'], note: 'V7♯9 — the minor-key dominant with grit, one fret below ♭VI' },
+          { shape: M11_C, extensions: ['11'], note: 'i11 — dark and hollow' },
+          { shape: M9_6, extensions: ['9'], note: '♭vii9 — low root, 9 on top' },
+          { shape: DOM13_6, extensions: ['13'], note: '♭III13' },
+        ],
+        tips: 'The verse-register version: fewer notes, lower voicings, and the ♯9 on the V because in a minor key the dominant wants tension. Save the first play\'s glossy 9ths for the hook — the contrast between the two sets is the arrangement.',
+      },
+    ],
+
+    'rnb-chromatic-vi': [
+      {
+        label: 'Chromatic descent on the A string',
+        level: 'intermediate',
+        chords: [
+          { shape: SIX9_5, extensions: ['6', '9'], note: 'I6/9 — Motown sunshine on the tonic' },
+          { shape: M9_5, extensions: ['9'], note: 'vi9 — root high on the A string' },
+          { shape: DOM9_5, extensions: ['9'], note: '♭VI9 — the borrowed dominant, one fret down' },
+          { shape: DOM9_5, extensions: ['9'], note: 'V9 — one more fret: the slide lands' },
+        ],
+        tips: 'The last three roots fall one fret at a time down a single string — vi, ♭VI7, V is chromatic planing, the same trick as the jazz tritone sub seen from above (♭VI7 subs for II7). Target the ♭VI7\'s 3rd: it slides a half step down onto the 3rd of V.',
+      },
+      {
+        label: 'Low-string 13th descent, triad on top',
+        level: 'intermediate',
+        chords: [
+          { shape: TOP3_MAJ, note: 'I — a bare high triad; let the bass state the root' },
+          { shape: M9_6, extensions: ['9'], note: 'vi9 — drop to the low-E root' },
+          { shape: DOM13_6, extensions: ['13'], note: '♭VI13 — one fret down, horn-section colour' },
+          { shape: DOM13_6, extensions: ['13'], note: 'V13 — one more fret; hold it for the horn hit' },
+        ],
+        tips: 'The register story: start thin and high, then walk the low E string down in half steps with big 13th colour — the guitar plays the horn line. Punch the two 13ths on the beat and mute instantly; Sir Duke swings because of the silence between hits.',
+      },
+    ],
   },
 
   improv: {

src/data/kb/rnb/progressions.js

@@ -1,3 +1,11 @@
+// Level tags + the two intermediate progressions added by task P-20.
+// Intermediate-entry changes verified against: guitarmusictheory.com &
+// Hooktheory TheoryTab & musescore.com feature ("Just the Two of Us" —
+// D♭maj7–C7–Fm7 with the E♭m7–A♭7 ii–V pointing back at ♭VI, key of F minor),
+// Hooktheory TheoryTab & songdna.blogspot.com & spytunes.com ("Sir Duke"
+// verse B–G♯m–G–F♯7 = I–vi–♭VI7–V chromatic descent),
+// docs/progression-repertoire.md §2 (modal interchange, secondary dominants,
+// tritone substitution rows).
 export default [
   {
     id: 'rnb-mediant-circle',
@@ -9,6 +17,7 @@ export default [
     mode: 'major',
     songs: ['September — Earth, Wind & Fire (rotation family)', 'the soul turnaround started from the iii'],
     tip: 'The 1-6-2-5 family entered from the mediant — home is implied for three bars before the V finally points at it. Neo-soul lives in that deferral.',
+    level: 'foundation',
   },
   {
     id: 'rnb-6251',
@@ -20,6 +29,7 @@ export default [
     mode: 'major',
     songs: ["Isn't She Lovely — Stevie Wonder"],
     tip: 'The II is a secondary dominant (not the polite ii), and the V arrives as a 9sus — suspended, never quite dominant, melting into the I. Stevie\'s whole cadence language in four chords.',
+    level: 'intermediate',
   },
   {
     id: 'rnb-maj7-vamp',
@@ -31,6 +41,7 @@ export default [
     mode: 'major',
     songs: ['Waiting in Vain — Bob Marley', "Cruisin' — Smokey Robinson (I–ii7 variant)"],
     tip: 'Two lush chords trading forever — the song is the texture. The same vamp underpins half of modern bedroom R&B; colour it differently every two bars.',
+    level: 'foundation',
   },
   {
     id: 'rnb-dorian',
@@ -42,6 +53,7 @@ export default [
     mode: 'dorian',
     songs: ["Spanish Joint — D'Angelo", "Didn't Cha Know — Erykah Badu (i–iv minor variant)", "Brown Sugar — D'Angelo (E Dorian loop)"],
     tip: 'The IV9 carries the raised 6th that makes it Dorian — the same pair as the funk vamp, slowed to 70 BPM and dragged behind the beat.',
+    level: 'foundation',
   },
   {
     id: 'rnb-gospel-amen',
@@ -53,5 +65,30 @@ export default [
     mode: 'major',
     songs: ['the gospel "Amen" cadence', 'countless soul ballad turnarounds (borrowed iv)'],
     tip: 'The IV turns minor on its way home — borrowed from the parallel minor, the single most-borrowed chord in soul. One semitone (the 3rd of the IV falling) does all the work.',
+    level: 'intermediate',
+  },
+  {
+    id: 'rnb-justthetwo',
+    name: 'Just-the-Two-of-Us loop (♭VI–V–i + ii–V of ♭VI)',
+    rn: ['♭VImaj7', 'V7', 'i7', '♭vii7', '♭III7'],
+    degrees: [8, 7, 0, 10, 3],
+    qualities: ['maj7', 'dom7', 'min7', 'min7', 'dom7'],
+    bars: [1, 1, 2, 1, 1],
+    mode: 'minor',
+    songs: ['Just the Two of Us — Grover Washington Jr. & Bill Withers', 'a smooth-soul/90s-R&B staple loop'],
+    tip: 'A minor loop that spends most of its time away from home: ♭VI–V–i falls in half steps, then the ♭vii–♭III7 is a ii–V aimed back at ♭VI, not at i. Hearing ii–Vs that target chords other than the tonic is the door out of diatonic playing — in the original the last two chords share one bar.',
+    level: 'intermediate',
+  },
+  {
+    id: 'rnb-chromatic-vi',
+    name: 'Chromatic soul descent (I–vi–♭VI7–V)',
+    rn: ['I', 'vi7', '♭VI7', 'V7'],
+    degrees: [0, 9, 8, 7],
+    qualities: ['maj', 'min7', 'dom7', 'dom7'],
+    bars: [1, 1, 1, 1],
+    mode: 'major',
+    songs: ['Sir Duke — Stevie Wonder (verse)'],
+    tip: 'One swapped chord makes it: where the diatonic loop would repeat vi or move to IV, the ♭VI7 (borrowed from the parallel minor) slides the bass down 6–♭6–5 in half steps. It doubles as a tritone sub of II7 (V/V) — either way the whole chord planes down a semitone into V.',
+    level: 'intermediate',
   },
 ]