I'm basically on mandatory vacations until May, so time for a long ass post lol.
So people are saying Kimetsu No Yaiba should receive a color chapter, and I mean it could happen.. I guess maybe, but then again super popular authors like Togashi or Watsuki never got one.. (I think? I'm too lazy to check any of those particular author's series as I don't have the kanzenbans nor any Jump issues with cp of them.. I should say Color Pages lol, writting CP and Watsuki in the same sentence could lead to misunderstandings in context/meaning.)
Anyways, Out of the top of my head, and I might be forgetting some series:
Endings:
-Ring Ni Kakero.
-Slam Dunk.
-Dragon Ball.
These 3 had their entire endings with Color Pages + Bichrome.
-Pyu To Fuku! Jaguar.
Last chapter was in Bichrome.
(You can click here but it will spoil you the ending of Jaguar! You have been warned!! Not.. Not really lol, just click the link, you probably weren't going to read a 400+ gag manga that hasn't even been fully scanlated yet anyways)
-Naruto:
Last chapter is entirely in color (as in no Bichrome, real full color, sadly it looks digitally colored I think, I would have love to see Kishimoto's copic coloring style).
Not endings:
-Bleach
-Eyeshield 21
-Prince of Tennis
All these 3 series received Full color entire chapters (No bichromes) in argueably their "climaxes", or the climax of certain arcs, I remember Bleach was the Ichigo vs Byakuya battle, and PoT was a match against Hyotei (which was/is the most loved tennis club in the series, after Seigaku of course.. Though Atobe is probably the most liked character.. who knows, but he's certainly given the most
Giri Choco every year
I'm not sure about Kochikame, but I'm almost positive it didn't get a full color page ending?
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Now, the thing is that Full Color chapters aren't as rare as most would assume.
What was and still is pretty rare is a series ending with full colored chapters (Be it Full Color+ Bichrome, like the first 3 I mentioned/ Just Bichrome, like Jaguar/ Just Full Color, like Naruto).
But color chapters were quite frequent before the 90s, just not Full Color chapters, more like 3 Full Color pages and then 15+ pages of Bichrome pages.
Just looking thru some old WSJs of mine and the Saint Seiya Kanzenbans I saw that
some but not every chapter that got a color page during the 80s was the entire chapter.
For example in the 1986 Issue 1-2, which was the Saint Seiya debut
the entire first chapter is colored (3 Full Color pages, the rest is bichrome), now remember this was the debut of a series by veteran author Masami Kurumada the very same author whose last series Ring Ni Kakero was the first ever series in Jump to receive a full color ending, so probably Saint Seiya got special treatment, I don't think
every Jump series had a full color first chapter pre 90s
.
Issue 38 of 1989 (which I bought because it's my literal birth date, now you know how old I am)
has an entire full color chapter of Jojo but the next series after Jojo (Which was front series)
is the Momotaroh, which only had like 7 Bichrome pages and the rest was normal black and white.
Also.. I'm pretty sure Dragon Ball had some full color chapters too, it had plenty of Full Color+Bichrome, but I also distinctly remember some chapters being full colored.
After the 90s bichrome was less and less used, I can remember for example that the first chapter of One Piece has bichrome pages, Hunter x Hunter's first chapter too BUT series like Shaman King which also debuted in 1998 or Naruto (1999) didn't have bichrome in the first chapter, so it seems like the use of bichrome pages for manga started to decline or ended in 1998.
But bichrome never entirely left the pages of Jump, it is still used to this day, mostly in advertisement pages.. I can't really remember the last time a manga actually had bichrome pages in Jump though it was probably Jaguar.. Idk.
All that being said It'd be cool for Kimetsu no Yaiba to get a full color ending, I don't think it should get one if series like BLEACH or Kochikame didn't get one (I know it has sold more than those series per volume) but I think if Gotouge is cool with the extra workload the final chapter in full color would be a great final publicity stun (like the series needed it lol).