The 121Z is dealt on the current models page

The Yamaha RGX 100 range

I don't intend to go into a huge amount of detail on these, they are the bottom of the range and whilst there are some really good guitars there are also some of the worst guitars Yamaha produced. I will deal with them in groups according to pickup configuration.

The RGX110

This single humbucker guitar featured trapezoid tuners, which are amongst the worse types fitted to any guitars. It was produced from 1987 to 1991 they are in western catalogues but not in Japanese ones nor are they in the Archives Yamaha has made some very good single pickup guitars but this isn't one of them. Made in Taiwan.
Specifications
Body Basswood
Neck Bolt on Mahogany Painted Black
Fretboard Buvingha 628mm scale 350mm radius 24 Frets Dot Markers 2 at 12th and 24th Fret
Headstock see pictures
Tuners Chrome Traps
Pickups 1 Ceramic Humbucker
Controls 1 Volume 1
Nut Urea not locking 43mms
Hardware Chrome
Bridge Vintage 11
Pickguard None
Colours Black, White, Red or Power Purple

Some Pictures

 

RGX120D

This guitar was produced from 1994 to 2002. Made in Taiwan again only in the Western catalogues not the Archives or Japanese catalogues
Specifications
Body Alder
Neck Bolt on Maple
Fretboard Rosewood 648mm scale 350mm radius 22 Frets Dot Markers
Headstock see pictures
Tuners Chrome Diecast
Pickups 2 Ceramic Humbuckers
Controls 1 Volume 1 Tone 3 way switch No coil tap
Nut 43mms not locking
Hardware Chrome
Bridge Vintage Vibrato
Pickguard None
Colours Black, White or Vintage Red

Pictures

The RGX112 range

There are 2 models in the western catalogues the 112 and the 112P, the archives refer to a 112JII and I have seen pictures of a 112J. So probably 4 models.
So taking the "Western models" first

The 112



The 112P note more than one headstock design

The 112JII appears in the archives but I can find no other reference to it there are pictures of a 112J about but no other information so specs from the archives of the 112JII


Specifications
Body Alder
Neck Bolt on Mahogany
Fretboard Bubinga 628mm scale 350mm radius 24 frets
Tuners Chrome
Pickups 1 GHF1B Humbucker 2 GSF3B Scs
Controls 1 Volume 1 Tone 3 way switch No coil tap
Nut
Hardware Chrome
Bridge Vintage II Vibrato
Pickguard None
Colours Black or White
Produced 1990-1991

Some pictures of the 112J which may or may not be the same guitar

The RGX 112JII was available as part of the
First Stage Street Style
This was a guitar and Amp deal with all you need to start playing, similar to deals done with Pacificas and Squiers.
There were in total six guitars all with the same accessories but priced according to the guitar these are:
FS1 RGS 103p 55000 yen
FS2 RGS 112p 55000 yen
FS3 RGS 312p 68000 yen
FS4 RGX 112 JII 59000 yen
FS6 RTX 102 58000 yen
FS7 RTL 102 58000 yen

Note there is no number 5 and FS6 and FS7 are described as new suggesting there was an earlier deal including another guitar as FS5 but there is nothing in the 1990 catalogue and nothing in any western catalogues that I can find

The Guitar part of the catalogue scan. There was a Bass version available as well

The RGX121s

Models
The 121 D & DM
The 121S
The 121
The 121FP
The 121SJ
The 121Z Covered in current models

These guitars were made from 1991 to 1994 in Taiwan. they are essentially the same guitar but with the addition of the free art pickguard (see RGX intro page)

Specifications
Body Alder
Neck Bolt on Maple
Fretboard Bubinga 648mm scale 350mm radius 22 frets
Tuners Chrome diecast
Pickups 1 single coil 2 Humbuckers not specified
Controls 1 Volume 1 Tone 5 way switch No coil tap
Nut not locking
Hardware Chrome
Bridge Vintage II Vibrato
Pickguard None (Free Art on the FP)
Colours Black or White Vivid red on the 121 only

The Headstocks
 


The 121 top next 121FP and a decorated 121FP

These guitars are the same model differing only in the board and the colours made in Taiwan from 1995 to 2000 appearing only in Western catalogues.

Specifications
Body Alder
Neck Bolt on Maple
Fretboard Rosewood or Maple 648mm scale 350mm radius 22 frets dot markers
Tuners Chrome diecast
Pickups 1 single coil 2 Humbuckers not specified
Controls 1 Volume 1 Tone 5 way switch No coil tap
Nut not locking
Hardware Chrome
Bridge Vintage Vibrato
Pickguard None
Colours 121DM Blue Indo, Antique Sunburst or Satin Black
121D Black, Red, Natural Satin

Some Pictures

The 121S appears in several catalogues and was made from 2000 to 2003 the SJ appears nowhere that I can find but pictures showing serial numbers show that the guitar was made around 2003 in both Taiwan and Indonesia. I am not sure of the full specs for the SJ I haven't been able to find them anywhere so the info below is as far as the SJ is concerned is from reviews sales etc and is incomplete all additional information welcome.

These guitars are very similar and other than colours and slightly different headstocks I am hard pushed to distinguish between them
Update October 2021
Stephen who is from Australia and has the guitar site www.lonephantom.com has been in touch with Yamaha who have told him that the SJ has the same specs as the S but is made in Indonesia not Taiwan. Thank you Stephen
November 2021
Peter Moulton who has provided me with a lot of information on 100 series Pacificas (see relevant page) has the following observation.
Your photo of a right handed RGX-121S in Shelby Blue shows black die-cast tuners that are pin mounted, yet on my left handed RGX-121SL in Shelby Blue, the left handed stock black die-cast tuners are 135 degree screw mounted.

The above are pictures of the 121S below are the SJ