Kurosawa’s influence on Lucas has been so thoroughly discussed and dissected by this point that I have little to add. But if, for whatever reason you’ve never explored the connection for yourself, you’re in for a treat. Start with 1958’s The Hidden Fortress (aka Kakushi toride no san akunin or The Three Villains of the Hidden Fortress). 

You’ll notice some superficial similarities, especially Kurosawa’s heavy use of wipe transitions, which Lucas employed liberally in Star Wars. But after just a few minutes’ worth of viewing, you should start seeing deeper parallels. There’s the fact that the peasants Tahei and Matashichi map nearly perfectly to Artoo and Threepio, in personality as well as their relationship to the other characters and their roles as catalysts of the plot. Kurosawa’s film also features a battle-weary general who becomes wrapped up in a rebellion led by a princess. Even the overall story beats for both films follow a very similar structure. When you get right down to it, Star Wars is effectively a remake of The Hidden Fortress, something Lucas himself has admitted to on several occasions. 

But Kurosawa’s influence can’t be limited to one film. You should also check out 1961’s Yojimbo, which provides definitive proof that Lucas was directly inspired by Kurosawa, and not merely Kurosawa by way of Leone. If you don’t understand the distinction, it helps to know that Leone’s A Fistful of Dollars was such a blatant ripoff of Yojimbo that Kurosawa sued. 

But there’s one distinctive element of Yojimbo that Leone didn’t pilfer, but which made its way into Lucas’s movie. Check out the first fight in the film. Imagine Toshirô Mifune wearing Jedi garb instead of samurai robes, and holding a lightsaber instead of a katana. (That shouldn’t be too difficult, since Lucas actually wrote the role of Obi-wan Kenobi for Mifune, and only asked Sir Alec Guinness to play the part after Mifune turned him down.) Now imagine the scene as a gloomy cantina instead of a dusty street. What you’ll notice is that the fight plays out strikingly similarly to the cantina brawl in Star Wars, complete with the severed-limb gag that would appear in practically all of Lucas’s Star Wars films.

It wasn’t merely Kurosawa’s samurai epics that inspired Lucas, though. You should also check out 1975’s Dersu Uzala, a Soviet/Japanese collaboration about a Nanai trapper and hunter by the same name. Noteworthy for being Kurosawa’s only 70mm film, it came out not long before Lucas began filming A New Hope, and you can see visual influences throughout. 

Perhaps the most striking involves a scene in which the two main characters look out over a horizon that includes both the setting sun and the rising moon. You can catch a glimpse of the scene about a minute into the film’s trailer, although the visuals there don’t do it justice. Unfortunately, the only way I know of watching Dersu Uzala, short of buying a disc, is on The Criterion Channel, but since that streaming service is also home to many of Kurosawa’s classic films, it may be worth signing up for a 14-day trial if you don’t want to buy them on Blu-ray.