Chairs with curved back rests: A reference list.  

the only nice thing of this one is likely the sapwood on the armrest.

Whenever I have seen those chairs, I have assumed those armrests are rosewood and the rest is stained beech. Is that right?

That’s indeed possible, or possibly another cheap tropical wood. 

and here another enigmatic chair with curved backrest

@andersen. Hong Stolefabrik. I don't know the model number. 

Saw a couple marked with "51".   One with wood backrest was marked "51" and this one with upholstered backrest is marked "51A".  Both attributed by sellers to Erik Kirkegaard.  Don't know if those are for year produced or model#.

@mark737. I would say it is model number. Thanks.

@andersen.  You could add this chair to the "Hong Stolefabrik " thread, as it is not listed there.

https://designaddict.com/community/main-forum/hong-stolefabrik/#post-173670

Thankyou @andersen for posting.

@andersen @lexi @mark737 Model 51 makes sense. Referring to the DFI, other Kirkegaard chairs have been identified as models 43, 49, 53 or 56. For this specific chair the index references Mobilia, which makes me think that Kirkegaard was indeed the designer. The aforementioned chair is model 43, also by Kirkegaard.

A similar chair that I don't think has come up previously.  "Carlton" chair made by Jakob Låte Møbelfabrikk, Odda Norway Established in 1933.  This is per Jon Låte on the Norwegian furniture Facebook site.  I saw at least one seller attribute to Theodor Harlev for Farstrup.  

@mark737. That Carlton chair pops up all the time on that Norwegian FB Forum.

@mark737 Forgive me but I edited your post (yes, I can do that) and changed Harlevs first name from Thomas to Theodor. Just because it’s correct. Although I doubt the chair is Farstrup.

Update on the infamous " fire chair/T21 " that has has has us all scratching our heads!

Found an image and information on Instagram.

Model 68, made by ANDERSTRUP Stole/Mobelfabrik !

post script; tagging @gropius seeing as he posted this chair.

Arne Wahl Iversen for Soroe Stolefabrik. 

@herringbone. Nice. Nothing beats a vintage advert. Thank you for posting.

 Kai Kristiansen , model 61 chair ;manufactured by S B Feldballes Mobelfabrik.

Image from  God Form. Dansk købestævne 1957

Edit:- As pointed out by @vildbjerg-lkj ( following  post) most likely NOT produced by S B Feldballes Mobelfabrik.