Egomaniac's LP is far and away the definitive Kenzan translation, with everything including all sidequests being translated and having a natural conversational flair, the full translated text superimposed onto the videos themselves, like the more well-known KHsubs LP but much better
The ASMR explanations of actual Japanese feudal history by an expert are a welcome bonus and genuinely made me feel like I learned something

Playing this game with his LP on a second screen and pausing to sync up with the cutscenes is the best way to play this game and I got a lot of enjoyment out of it
What an immense amount of effort for something only a couple thousand people have appreciated after 10+ years
Reward his efforts and treat yourself to the best translation of this game that will probably ever exist

Great characters too, Sasaki Kojiro (the original Sephiroth!) will strike the fear of God into you and Marume Nagayoshi steals the screen every time he makes an appearance
Miyamoto Musashi (alias Kazumanosuke Kiryu) offers a compelling view into an alternate reality in which Kazuma Kiryu has a sex drive
The masters over at the Houzouin are more compelling than a lot of characters that were introduced in the other PS3 Yakuza games

If you're a fan of this series you're missing out if you don't play this, go to LParchive/Youtube, sync up those cutscene subtitles on a second screen when a cutscene starts and go to town

I went through this series in release order but played this after Dead Souls and before 5 because the anniversary montage in the Dead Souls credits showing beautiful cutscene cinematography from this game made me feel like I was missing out
And I was missing out, it's a great game and despite Yakuza 2 having insane production values and feeling like an excellently written movie that actual people would watch willingly, Kenzan was the breakout moment that ensured Yakuza would have more cultural staying power than Urban Reign or Beat Down: Fists of Vengeance

As many have said this game will likely never get translated officially because a significant amount of the plot involves the implication that Haruka has been sold into slavery and you have to earn back her freedom, and at least once you will have to beat the shit out of someone infatuated with her
But this game was set before the turn of the first millennium and I felt like it did a tasteful job (for a Yakuza game) of empathizing with the women of the Tsuruya while not wallpapering over the historical reality that women did not have personhood in the Edo period
I don't know, I guess they could probably make it work in English if people wanted it bad enough, but that's the "Michael Jackson Sonic 3" "Beatles references in Earthbound" word on the street reasoning that people provide for the lack of a translation and who knows if that's real or if it'll ever get resolved

So don't hold out, if you're a fan of this series it's about time to boot it up, and if you play through in release order starting with the PS2 games like me, slot this one in-between Yakuza 2 and Yakuza 3 and you'll be glad you did, it has sidequests that tie into some from Yakuza 1/2 somehow, bespoke mechanics in the classic PS3 engine that would never reappear in a modern setting, and the PS3 era Yakuza games call back to this one enough to where it'll enhance your enjoyment of those later games, most notably one of Yakuza 5's locales is set in the modern-day Gion, where Kenzan was set over a millennium prior
And they do bold stuff in this game that they wouldn't be able to get away with using Kiryu because Kiryu is too on-model now, too manicured as a character
tl;dr: good game worth the trouble of playing in a kind of unnatural way, as opposed to not playing it at all, if you're hARDCORe like me it beats the hell out of not playing it