While not wanting to stir up the whole originals-versus-prequels debate, there is one simple factor that will forever set them lightyears apart. Every kid in every playground from 1977 to this day could tell you the answer. He remains the difference between Star Wars and every other sci-fi mythos going.
Every kid wanted to play him, not Luke (or, worst of all, Threepio). He just made it all work. Surly, wisecracking, dismissive, a dab hand with a blaster, the best pilot-smuggler in the galaxy, and best friends with a Wookiee. Jedis can go hang - we're with the cool cat in the waistcoat.
George Lucas managed to launch Steve McQueen's Cooler King, Clint Eastwood's Blondie, Vegas-era Elvis, Frank Sinatra, JFK, Lenny Bruce and goddamn Indiana Jones (although we didn't know it yet) into space, all of them crammed into the handsome body of one Harrison Ford, one-time carpenter, shortly to become the biggest star in the world.
Forget the Force, forget Vader's overarching tragedy, forget the Death Star and lightsabers and Leia in that slave-girl bikini get-up. When it comes to what makes Star Wars the greatest fucking science-fiction story ever told, the answer is Han Solo.
The story of his casting is as well-worn as the movies themselves - that he was only used by Lucas to read in auditions; Nick Nolte and William Katt were the favourites, but this young actor was layering the lines with a sly sarcasm that won him the part. It is well-known Ford thought it was all so much hooey and treated the script with something like disgust.
"Hokey religions and ancient weapons are no match for a good blaster at your side, kid," he quoted with a superiority gained through nothing but cocky self-confidence. Right there, Lucas realised this would be the making of the character who had started life as a green-skinned alien with gills.
When he arrives in the movie - actually when the movie arrives at his table at the back of the Cantina - the saga springs to life in a way we never could have imagined. It becomes cool. Ford's rancour remained throughout the shoot, but the character grew and grew, feeding off his spiky backhanders.
He is almost a postmodern conceit, a character who comments on the plot as he rides along with it. Solo single-handedly (okay, Chewie helps) prevents the original trilogy from giving in to its own pomposity. "You have to force yourself!" he quipped when pushed by testy interviewers on how he chewed out those silly lines. That's just it - by taking the piss, he was making the material live.
He was also being somewhat disingenuous. The part is smartly written and grows with each film, hidden depths emerging from beneath the 'space cowboy' swagger, and an unforeseen romance blossoms. This was the first of the sequel's many shock turns - we were still suffering under the illusion Luke was going to romance Leia. Ford's sparring with Fisher deviated into Bogart/Bacall territory: a film about space knights and shiny droids was gaining, of all things, sass. Solo was giving us his second gift - beyond the cool we were getting heart. Jeez, the ending of The Empire Strikes Back is savage.
How could a comeback to Leia's confession of love as peculiarly ungiving as "I know" work so well without old-fashioned decent acting? As he is frozen in carbonite and sent off with Boba Fett towards Jabba's court, small boys left the cinema with a totally new sensation: pain. Playgrounds were desolate; foul rumours had it he would never return.
Ford did of course come back, but not without pressuring Lucas to kill off Solo (he had Indy simmering nicely, superstardom was a breath away). The director sensibly ignored such importuning: "He didn't want me killed by those teddy bear guys," smarted Ford in pure Solo-ese. The crossover was obvious; so much of Solo's bone-dry delivery and touchy attitude stemmed directly from planet Harrison.
The part was three-dimensional, he retorted to his critics - "The third dimension is me." Any other actor, even loopy-lanky Christopher Walken (a near-miss), is unthinkable.
Then there are the simple things. A lot of which are down to Lucas' creative nous. Solo happens to be the owner of the Millennium Falcon, the ship that can do the Kessel run in fewer than 12 parsecs, for heaven's sake. He can speak Wookiee, or at least translate. And, while others had judo suits or woollen hoodies, he always looked the business; the guy just never let it slip. He even went unsullied by the prequels: an idea to have a junior Solo hanging out on the Wookiee homeworld was sensibly ditched at the concept stage.
Solo stands apart, the jaunty counterpoint to all that holy Jedi pontificating: "Kid, I've flown from one side of this galaxy to the other, and I've seen a lot of strange stuff. But I've never seen anything to make me believe that there's one all-powerful Force controlling everything. There's no mystical energy field that controls MY destiny." You may stand in awe of Vader, or Yoda, or Obi-Wan, but you want to be Han Solo.