Although it was their fifth album, In Rock was the record that established Deep Purple as one of the genre-defining hard rock bands. The early albums by what became known as the mark I version of the band, featuring Rod Evans on vocals, had been a mixture of late-60s psychedelia and pop with few hints of what the band would later become. All that changed with the arrival of Ian Gillan and Roger Glover to form Deep Purple mark II. The album’s opening number begins with an ear-splitting wall of shredding guitar, before Blackmore unleashes that raw and dirty riff while Gillan cut-and-pastes fragments of well-known rock’n’roll lyrics. For the instrumental break it changes tack, with a call-and-response between Blackmore’s very bluesy licks and Jon Lord’s organ. There are strong echoes of the rock’n’roll that Blackmore paid his dues playing at end-of-the-pier shows in the 60s, but this was rock’n’roll turned up to 11.

Compared with the full-tilt hard rock of In Rock, 1971’s Fireball was a rather more experimental affair, less immediate than its predecessor, which sometimes gets overlooked. It’s an album Blackmore himself sometimes dismissed in interviews, and it was only after he left the band for good in the 1990s that Purple started featuring much of the record in live sets. No No No is one of the album’s highlights, showcasing several aspects of Blackmore’s playing. First there’s that slightly funky riff, then there’s the blues flourishes between the verses, and then there’s not one but two back-to-back solos, the first of them being one of the earliest examples of his distinctive sustained slide style that was to feature heavily in Blackmore’s playing later in the decade.

1972’s Machine Head and the subsequent live album Made in Japan – which drew heavily from it – are rightly regarded as among Deep Purple’s definitive statements. Everybody knows Smoke on the Water with that riff, but the other great Machine Head anthem on that album has to be Highway Star, for many years their set-opener. Gillan’s paean to boy racers has exceedingly cheesy lyrics, but that’s not the point; this is a song that evokes the feeling of driving a souped-up Ford Capri at way above the legal speed limit. Blackmore’s playing is like a force of nature on the live version; those slashing chords in the intro, and that amazing solo featuring the distinctive neo-classical descending runs, combining the spirits of Bach and Jimi Hendrix.

Gillan’s decision to leave Deep Purple in 1973 citing burnout prompted Blackmore to change direction, sacking Roger Glover and recruiting Glenn Hughes and the then-unknown David Coverdale to become Deep Purple mark III. Parts of the new incarnation’s first album took on a soulful, bluesy flavour quite different from what had come before, but the title track – an out-and-out rocker featuring one of Blackmore’s best riffs and more neo-baroque flourishes in the instrumental breaks – showed what they could do with two strongly contrasting lead vocalists.

By the time of the followup album Stormbringer, the new recruits took on a bigger share of the writing, and Blackmore wasn’t happy with the direction they took, especially the soul and funk elements bought in by Hughes. But if Blackmore didn’t like funk, that didn’t mean he couldn’t play it, and the rhythm playing on this song is quite unlike anything he recorded before or since. There are not many songs featuring Blackmore’s guitar that would benefit from a 12” remix, but this is one of them. But ultimately his dissatisfaction with this sort of material was to see him leave Deep Purple and start the next chapter of his career: Rainbow.

The combination of Blackmore’s increasingly classical-flavoured guitar playing with Ronnie James Dio’s operatic voice and dungeons-and-dragons lyrics proved a perfect match on the three Rainbow albums they recorded together. They began to work together while Blackmore was still in Deep Purple, but the supposed side project took on a life of its own. The high point of their collaboration was Stargazer, the centrepiece of the second Rainbow album, Rising. Dio’s lyrics tell a tale of a wizard consumed by hubris – it sounds like a metaphor for working in a failed dotcom startup – and the music is a monstrous near-symphonic epic that manages to outdo Led Zeppelin’s Kashmir. The jaw-dropping, eastern-flavoured solo is the work a man at the very height of his powers.

Blackmore’s live work in the second half of the 70s, both with Purple and Rainbow, often included extended improvisational workouts; what had been five- or six-minute songs in the studio stretched to 20 minutes or more. These sorts of self-indulgent wig-outs were a thing of their time and aren’t something anyone is allowed to do nowadays, but when Blackmore was on form they could be magnificent. Rainbow’s version of the mark III Deep Purple song is a great example. It starts with a series of Echoplex runs building from a whisper to a wall of sound before he launches into the riff. Then, when it comes to the extended solo in the middle, rather than playing at 11 all the way through, he dials it right back with a series of blues and classical flourishes. It’s also remarkable for the way Dio takes Coverdale’s song and makes it his.

Blackmore hired and fired sidemen throughout Rainbow’s history. No two studio albums featured the same lineup, and only a handful of musicians lasted more than one album. By the time of Down to Earth in 1979, Dio had gone, replaced by Graham Bonnet; Roger Glover, whom Blackmore had sacked from Deep Purple a few years earlier, joined as bassist and co-writer. The band took a more commercial direction that saw them hit the singles chart, but the album standout was Eyes of the World, combining that commercial approach with something of the epic feel of the Dio era. Keyboard player Don Airey sets the scene with a menacing intro that references Holst’s Mars and there are some spectacular pyrotechnics in the instrumental break by the man himself.

This instrumental, which appeared as the non-album B-side of All Night Long, is a thing of beauty, and the fusion of rock guitar with classical motifs formed a template for a number of similar tracks on subsequent Rainbow albums. As an improvisation on a theme it’s more an instrumental piece than just an extended guitar workout. Blackmore avoids ruining things by overplaying, recognising that less is often more, something that showboating imitators like Yngwie Malmsteen would be well advised to pay heed to.

Ritchie Blackmore has continued making music over the past 30 years. He’s been part of a reformed Deep Purple, formed another short-lived incarnation of Rainbow, and for the past two decades has led his medieval folk-rock troupe Blackmore’s Night. He still comes up with occasional flashes of brilliance. But to end with, we’ll go back to the last truly great album he made, the 1984 Deep Purple reunion album Perfect Strangers. The reunited mark II lineup is firing on all cylinders here, with Blackmore’s serpentine riff, the barrelling rhythm section and Gillan’s exuberant vocal, even if the lyrics were stream-of-consciousness gibberish. Both Blackmore and Deep Purple have carried on making music since they went their separate ways, but neither were ever quite this good again.