The royal road progression (王道進行, ōdō shinkō), also known as the IV^M7–V⁷–iii⁷–vi progression or koakuma chord progression (小悪魔コード進行, koakuma kōdo shinkō),^[1] is a common chord progression within contemporary Japanese pop music.^[2]

It involves the seventh chords of IV, V, and iii, along with a vi chord; for example, in the key of C major, this would be: F^M7–G⁷–Em⁷–Am.^[3][2][4] The progression is also very often found with a vi⁷ chord in place of the vi, thereby making every chord in the progression a seventh chord.

The chord progression may be resolved with the tonic chord, for example in a IV^M7–V⁷–I or a ii⁷–V⁷–I progression.^[3] IV^M7–V⁷–iii⁷–vi–ii⁷–V⁷–I creates a full circle of fifths progression in the major mode, with V⁷ substituting for vii°. In C major, this would be F^M7–G⁷–Em⁷–Am–Dm⁷–G⁷–C.

The basic progression can be found in two versions. The first uses V⁷ in its third inversion (G⁷/F), the other uses V⁷ in its root position (G⁷).^[2] The former appears in lushly orchestrated pop arrangements, while the latter appears mainly in rock and electronic music.^[2]

In a minor key, there are two versions of the progression: VI^M7–VII⁷–v⁷–i and iv⁷–v⁷–III^M7–VI. The first version can be thought as an essential iv–v–v–i with the VI and VII chords substituting for the iv and v respectively, or as a VI–ii°–v–i with the ii° being substituted by the VII chord. For the second version, a cadential suffix may be added, such as iv⁷–V⁷–i or ii^ø7–V⁷–i. When resolved by ii^ø7–V⁷–i, a large progression iv⁷–v⁷–III^M7–VI–ii^ø7–V⁷–i is created, where the v⁷ substitutes for the VII. In A minor, this would be Dm⁷–Em⁷–C^M7–F–Bm^7(♭5)–E⁷–Am.

Variations on the royal road progression may include IV^M7–V⁷–I^M7–vi, ii⁷–V⁷–iii⁷–vi, or IV^M7–vii^ø7–iii⁷–vi for the major version, and iv⁷–VII⁷–v⁷–i, ii^ø7–VII⁷–v⁷–i, VI^M7–ii^ø7–v⁷–i, or iv⁷–VII⁷–III^M7–VI for the minor version(s).

When this progression is resolved by a ii⁷–V⁷–I cadence, it becomes IV^M7–V⁷–iii⁷–vi–ii⁷–V⁷–I, a sequence of descending fifths with V⁷ substituting for the vii° chord. The sequence of descending fifths was used regularly in tonal music since the Baroque era.

In Western pop music, the progression can be used without the seventh notes, so that it becomes IV–V–iii–vi. If resolved by an ii–V–I cadence, this becomes IV–V–iii–vi–ii–V–I.

The name for the progression, ōdō shinkō (王道進行), literally translates to "royal road progression". In Japanese, the expression ōdō (王道, "royal road") is used to describe an easy or painless method to do something.

An alternative term, koakuma chord progression, was originally coined by Japanese music producer Seiji Kameda on the 2014 NHK television show Kameda's Music Academy (亀田音楽専門学校, Kameda ongaku senmon gakkō). The phrase koakuma (小悪魔, lit. "little devil") is a phrase used to describe a seductive person who teases with one's feelings;^[5] as the chord progression involves two major chords in succession followed immediately by two minor chords, Kameda describes the moment where the progression moves from the major dominant chord to the minor mediant chord as akin to the moment of heartbreak induced by a playful lover, hence the name.^[6]

The royal road progression was originally influenced by jazz and rock progressions originating in Western music. The earliest example of the progression in J-Pop occurs in Yumi Arai's "Yasashisa ni Tsutsumareta Nara" (1974), closely followed by Arai's "Sotsugyou Shashin" (1975), released as a hit single by Hi-Fi Set in 1975.^[2] The opening of the latter song is very similar to Edward Elgar's "Land of Hope and Glory", which contains a IV−V^4/2−I⁶−vi (F-G⁷-C/E-Am) progression.^[2] Lowering the C in the C/E chord to B would give Em (iii), thus producing a complete royal road progression.^[2] Even if the lineage of the progression cannot be traced back to Elgar, the basic IV-V-I-vi progression could be considered a predecessor to the royal road progression, and this IV-V-I-vi progression was used in the Beatles' "I Want to Hold Your Hand", a hit in Japan in the 1960s.^[2]

Arai's use of the progression led to other 1970s and 1980s Japanese city pop artists, such as Hiroshi Madoka and Akiko Yano, using it.^[2] However, the progression reached a new level of popularity after its use in Stock Aitken Waterman's Eurodisco-influenced pop tracks such as Rick Astley's "Never Gonna Give You Up" and Kylie Minogue's "I Should Be So Lucky" (1987), the latter of which was a top 10 hit in Japan.^[2] In the 1990s, the immense popularity of Eurobeat in Japan furthered this trend,^[2] and the chord progression became so prolific in J-pop to the point where it has become a core part of modern Japanese music.^[4]

As of 2023, 40% of the top twenty best selling singles of all time in Japan contain the chord progression, and between 1989 and 2019, the year's top-selling Japanese song contained the progression 23% of the time.^[2] Pop music lacking the progression is often described as sounding "not Japanese". While artists' overuse of the ōdō progression can often be criticised as lacking in creative originality, the corpus of songs that become bestsellers in Japan and perform well on Japanese record charts feature plenty of tracks utilising the progression,^[4] thus contributing to the conservative nature of record labels that lean towards familiar progressions over more risky experimentation.

This is a list of recorded songs containing multiple, repeated uses of the IV^M7–V⁷–iii⁷–vi and similar progressions.

In Western music, the progression is sometimes seen without the seventh notes, or with some substitution for one of the chords in the progression. Examples include:

The Princess Kenny theme from South Park also used this chord progression. It contains western music imitating Japanese anime.

Sergei Rachmaninoff's Symphony No. 2 features a IV–V⁷–iii–vi–ii⁷–V⁷–I sequence in the third movement.^{[citation needed]}

Camille Saint-Saens' Aquarium movement from The Carnival of the Animals features an Am-F(Aug5)-G-E7 chord progression in A minor.

• I–V–vi–IV progression - four chord progression commonly used in Western pop music
• vi–IV–V–I progression - commonly known as the "Komuro progression" (小室進行, komuro shinkō), namesake of Tetsuya Komuro who popularised the progression.^[44]
• IV–vii°–iii–vi–ii–V–I - circle of fifths progression