Seiko has used many different materials for watch cases over the years. These greatly expanded in the late 70's and 80's when a range of different case materials were tested and various materials were employed to utilize their specific properties. The different materials used in the watch case construction are detailed in product catalogs and are often indicated on the case itself.
Seiko Serial Number
- Seiko watches use a 6 or 7 digit serial number stamped on the caseback. This serial number contains digits indicating the date. The first digit translates to the year and the second shows the month.
- How to find the serial number and movement/caliber number on a Seiko watch in order to then find the date of manufacture using serial-number-decoder.
This listing was initially created from the 1991 Seiko JDM dealer catalog but additional items have been added. The abbreviation is the case material that is listed in the catalogs and the case back stamping is what is often but not always marked on the watch case back.
The Seiko serial number database Details of the Seiko movement database Below is live information about the current Seiko movement database, it is updated regularly (scroll to the bottom to see last updated date). I am notified of movements which are searched for but not in there yet, when this happens I try to update it to include those. Serial Number: The serial numbers on modern Seiko models are comprised of 6 digits. The first digit indicates the year, the following character the month and the remaining 4 digits a unique production number. The month is listed as 1-9 for January to September, then 0 for October, N for November and D for December.
Here is an example of the case material codes from the 1991 Vol. 1 Catalog, e.g. SBBS018 has the case material code of THGMCETIHG, the SBBN001 has a code of TIHC.TI and the SSBT014 has TIHNT.TI.
The original 1991 listing from the JDM catalog can be downloaded from here - 1991 Seiko Case Codes JDM Catalog Vol1.pdf
Seiko Serial Number Database
See below for a table listing the various case material codes that have been used used.
| Abbreviation | Description | Case Back Stamping |
|---|---|---|
| 10KXS | Case of 10K yellow gold with reinforced inner body with SS | 10K BASE ST.STEEL ST.STEEL BACK |
| 10KYS | 10K yellow gold case, SS case back | 10K ST.STEEL BACK |
| 14K.GP | 14K yellow gold case, GP case back | 14KT BASE METAL BACK |
| 14KCE | Combined case with 14K yellow gold and ceramic | 14KT + CERAMICS ST.STEEL BACK |
| 14KXS | Case of 14K yellow gold with reinforced inner body with SS | 14K BASE ST.STEEL ST.STEEL BACK |
| 14KYS | 14K yellow gold case, SS case back | 14K ST.STEEL BACK |
| 18K | 18K yellow gold case | 18K (18KT) |
| 18KWG | 18K white gold case | 18KT |
| 18KYG | 18K yellow gold case | 18K (18KT) |
| AAPC | All Aluminum Palladium Alloy | AAPC |
| ABCRP | Black chrome plated case. Back lid black chrome plating | BASE METAL |
| ACRP | Chrome plated case. Back cover chrome plating | CRP |
| AGF | All Gold Filled | AGF |
| AGPRUP | Ruthenium-plated on gold-plated case of the cast-in-tone. Back cover GPRUP | BASE METAL |
| AHC | All Hard Coat, case coated with hard titanium nitride. Back cover HC | BASE METAL |
| AHGC | Case coated with hard titanium nitride. (Surface hardness or resistance to small scratches, Hv = 1200) Back side HCC | HGC |
| ALM | Rigid light alloy | ALM |
| ALSGP | All Light SEIKO Gold Colour Plated case | ALSGP |
| APDP | Case and case back with applied palladium plating. | PDP |
| ASG | All SEIKO Gold Plated case | SGP |
| ASGP | Gold plating. Gold back plated | SGP |
| ASILVER | All Silver. SILVER 850 is difficult to tarnish (sulfide) uniquely developed by SEIKO, it is a hard finish or fine silver | xxx SILVER or SILVER xxx |
| ASSGP | Part of stainless steel plated with gold. Partially gold-plated back cover | ST.STEEL+ BASE METAL |
| ATI | All Titanium case. (Excellent corrosion resistance and light weight) Backside Titanium. | TITANIUM |
| ATIHC | Titanium case coated with hard titanium nitride. (Same for rear cover) (In addition to the features on the titanium side, it is strong in surface hardness or high scratch resistance. Hv = about 1200) | TITANIUM |
| ATIHICDC | All TI case with super hard coating | TITANIUM |
| AWGF | All White Gold Filled | AWGF |
| AWGP | All White Gold Plating | AWGP |
| BCRP | Black chrome plated side. Back SS | BCRP ST.STEEL BACK |
| BCRP-PCD | Case combining black chrome plating and plastic resin. | BASE METAL+ PLASTICS ST.STEEL BACK |
| BTIHC.MBTIHC | All high intensity titanium | TITANIUM |
| CE | Ceramic Case (hard highly scratch resistant, Hv = 1500, no rusting, with a beautiful surface) ** | CERAMICS ST.STEEL BACK |
| CEAC | Case where the ceramic was coated with hard titanium nitride. | CERAMICS ST.STEEL BACK |
| CEHGC | Part ceramic on which the coating of hard titanium nitride was applied. | CERAMICS ST.STEEL BACK |
| CRP | Chrome plated case. | CRP ST.STEEL BACK |
| FRC | Blowing fluorocarbon resin to the lower side of the coating. | BASE METAL ST.STEEL BACK |
| FRC.PCD | Fused case combined resin coating and plastic resin. | BASE METAL+ PLASTICS ST.STEEL BACK |
| FRP | Fibre Reinforced Plastic | PLASTIC |
| GC | Gold Cap | GC |
| GF | Case affixed with gold. | GOLD FILLED ST.STEEL BACK |
| GHA | Case coated with hard titanium nitride. (Surface hardness is high resists against small scratches. Hv = 1200). | GHA ST.STEEL BACK |
| GPBCR | Gold plated and black chrome plated case. | BASE METAL ST.STEEL BACK |
| GPCRP | Gold plated and chrome plated case. | BASE METAL ST.STEEL BACK |
| GPCRP.GP | Gold plated and chrome plated case. Back side GP | BASE METAL |
| GPDP | Case combining gold and palladium plating. | SGP + PDP ST.STEEL BACK |
| GPDP.GP | Case combining gold and palladium plating. Back cover GP | SGP + PDP SGP BACK |
| GPHC | Case combining hard coating of titanium nitride. | BASE METAL ST.STEEL BACK |
| GPHGC | Case combining hard coating of titanium nitride and gold plating. | BASE METAL ST.STEEL BACK |
| GPRUP | Case on which the ruthenium plating was applied on the gold plating. | BASE METAL ST.STEEL BACK |
| GPWD | Gold-plated case, combined with reinforced wood. | BASE METAL + WOOD ST.STEEL BACK |
| HC | Case coated with hard titanium nitride. (Surface hardness or resistance to small scratches, Hv = approximately 1200) | BASE HC ST.STEEL BACK |
| HC.SSHC | HC bezel and middle with combined SS and HC back | BASE HC ST.STEEL BACK HC |
| HCBCRP | Coating of hard titanium nitride and the side subjected to black chrome plating. | BASE METAL ST.STEEL BACK |
| HGC | Case coated with hard titanium nitride. | HGC ST.STEEL BACK |
| HGCPC | Case combined with plastics by applying a coating of hard titanium nitride. | HGC + PLASTICS ST.STEEL BACK |
| HGP | Hard gold plated case. (Surface hardness is high and resistant to small scratches. Hv = about 500) | HGP ST.STEEL BACK |
| HSS | Case made of hard stainless steel. (Hv = about 450) | STAINLESS STEEL |
| HTIAGP.HTIA | Part of the hard titanium alloy on the case plated with gold | TITANIUM ALLOY |
| LSGP | Light colour SGP | SGP |
| MCOA | Cobalt hard alloy case. (Excellent in corrosion resistance and strong against small scratches. Hv = 500) Edge / Back SS | COBALT ALLOY ST.STEEL BEZEL.BACK |
| MHC | SS case coated with hard titanium nitride. | BASE METAL ST.STEEL BEZEL, BACK |
| MSS.HC | SS middle with hard titanium nitride bezel and back | ST.STEEL + BASE METAL ST.STEEL BEZEL |
| MSSGP | Case of SS plated with gold | ST.STEEL + BASE METAL ST.STEEL BEZEL,BACK |
| MSSPCD | SS bezel combined SS and plastic middle with SS back | PLASTICS ST.STEEL BEZEL |
| MTIGLC | Titanium coated with glass (surface hardness is higher than ordinary titanium, Hv = about 350-400) and SS. | TITANIUM ST.STEEL BEZEL,BACK |
| NSA | Super hard alloy side. (Surface hardness is high and resistant to small scratches, Hv = about 1200). ** | NSA STEEL BACK |
| NSACG | A part of the superhard alloy was coated with hard titanium nitride. ** | NSA+NSCG ST.STEEL BACK |
| NSAG | Super hard alloy case. (Surface hardness is high and resistant to small scratches, Hv = about 1200). ** | NSAG ST.STEEL BACK |
| NSAGCE | On the part of the case where the super hard alloy and ceramic are combined the coating of hard titanium nitride was applied. ** | TUNGSTEN CARBIDE + CERAMICS ST.STEEL BACK |
| NSB | The case sprayed with hard material such as ceramic. (Surface hardness is high and resistant to small scratches, Hv = about 700-1000). | NSB ST.STEEL BACK |
| NSCG | Case of super hard alloy coated with hard titanium nitride. (Surface hardness is high and resistant to small scratches, Hv = about 1200). ** | NSCG ST.STEEL BACK |
| NSCGCE | The case combining hard carbide and hard ceramic with hard titanium nitride. (Surface hardness is high and resistant to small scratches. Hv = about 1200) | TUNGSTEN CARBIDE + CERAMICS ST.STEEL BACK |
| NSP | Hard Alloy Processing | NSP |
| PC | Case made of plastic. | PLASTICS |
| PC.SS | Case made of plastic. Case back SS | PLASTICS ST.STEEL BACK |
| PDP | Case subjected to bare Palladium plating. | PDP ST.STEEL BACK |
| PDPRUP | Ruthenium plated case on palladium plating. | BASE METAL ST.STEEL BACK |
| PM | Platinum | PM |
| PMP | Platinum Plating | PMP |
| SGP | Seiko Gold Colour Plate. | BASE METAL ST.STEEL BACK |
| SGP30 | Case with 30 micron gold plating. | SGP30 ST.STEEL BACK |
| SHA | Hard alloy case. (Hv = about 700). | SHA ST.STEEL BACK NICKEL ALLOY ST.STEEL BACK |
| SHAGHA | A part of the hard alloy case is coated with hard titanium nitride. | NICKEL ALLOY ST.STEEL BACK |
| SHAHC | A part of the hard alloy case is coated with hard titanium nitride. | NICKEL ALLOY ST.STEEL BACK |
| SILP | Silver Plating | SILP |
| SILVER | Case made of silver. xxx represents value of silver / 1000 | xxx SILVER ST.STEEL BACK or SILVER xxx ST.STEEL BACK |
| SS | Case made of stainless steel. It is harder to rust than regular steel | STAINLEES STEEL |
| SS.PCD | Part of SS with plastic decorations. | ST.STEEL+ PLASTICS ST.STEEL BACK |
| SS18K | Case of 18K yellow gold and stainless steel combined. | ST.STEEL + 18KT ST.STEEL BACK |
| SSBCR.BCRP | Case of the ss plus black chrome plating. Back cover black chrome plating. | ST.STEEL+ BASE METAL BASE METAL BACK |
| SSGP | Case of SS with gold plate | ST.STEEL+ SGP ST.STEEL BACK |
| SSGP.G | Case plated gold on part of SS. Ruptured Gold Plating. | ST.STEEL+ BASE METAL BASE METAL BACK |
| SSHC | Part of ss coated with hard titanium nitride. | ST.STEEL+ BASE METAL ST.STEEL BACK |
| SSPCD.BCRP | Apply black chrome plating to part of SS, case plated with plastic decoration. | ST.STEEL+ PLASTICS+ BASE METAL ST.STEEL BACK |
| SSPCD.FRC | Fluorocarbon resin was sprayed on a part of SS and the case on which plastic decoration was attached. | ST. STEEL + BASE METAL MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| SSWD | SS case combined with reinforced wood. | ST.STEEL WOOD ST.STEEL BACK |
| STP | Stainless Steel Plating | STP |
| T14K.M14KWG | Case combining 14K yellow gold and white gold | 14KT ST.STEEL BACK |
| T14KHC.M14K | Case of 14K gold yellow gold coated with hard titanium nitride | 14KT ST.STEEL BACK |
| T18K | Case which combines 18K yellow gold and SS | ST.STEEL 18KT BEZEL |
| T18K.MSS18K | Case with 18K yeloow gold and SS | ST.STEEL+ 18KT MIDDLE 18KT BEZEL ST.STEEL BACK |
| T18K.MSSGP | Combined 18K yellow gold and SS with some gold plating | ST.STEEL + BASE METAL MIDDLE 18KT BEZEL ST.STEEL BACK |
| TALH.MBCRP | Hard aluminum case combined with black chrome plating. | BASE METAL MIDDLE ALUMINIUM BEZEL ST.STEEL BACK |
| TALH.MFRC | A coating of fluororesin was applied to the case combined with hard aluminum. | BASE METAL MIDDLE ALUMINIUM BEZEL ST.STEEL BACK |
| TALH.NSB | Case where the hard material was sprayed and hard aluminum was combined. | NSB MIDDLE ALH BEZEL ST.STEEL BACK |
| TALM.MPC | Case on which aluminum and plastic are combined. | PLASTICS MIDDLE ALUMINIUM BEZEL ST.STEEL BACK |
| TALM.MPCPDP | Palladium plating on case combined with aluminum. | PLASTICS MIDDLE ALUMINIUM BEZEL ST.STEEL BACK |
| TBCRP | Part of SS was subjected to black chrome plating. | ST.STEEL BASE METAL BEZEL |
| TBCRP.FRC.MBCRP | Black chrome plating and case with fluorinated resin coating. | BASE METAL ST.STEEL BACK |
| TBCRP.MFRC | Black chrome plating and case with fluorinated resin coating. | BASE METAL ST.STEEL BACK |
| TBCRP.MHC | The coating of hard titanium nitride and the case subjected to black chrome plating. | BASE METAL ST.STEEL BACK |
| TCE | Ceramic and SS combined case | ST.STEEL CERAMICS BEZEL |
| TCE.GP | Ceramic bezel, GP case | BASE METAL CERAMICS BEZEL |
| TCE.MTIHICDC | Ceramic bezel, TI with super hard coating case and back | TITANIUM + CERAMIC BEZEL |
| TCE.TIHC | Ceramic bezel, TI with super hard coating case and back | TITANIUM + CERAMIC BEZEL |
| TFRC | Part of SS was sprayed with fluorocarbon resin | ST.STEEL BASE METAL BEZEL |
| TFRC.MHC | Case coated with fluororesin and hard nitride nitride | BASE METAL ST.STEEL BACK |
| TGP.MCOA | Case with gold plated bezel and cobalt hard alloy are combined | COBALT ALLOY MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| TGP.MGPBCRP | Black chrome plated and gold plated case | BASE METAL ST.STEEL BACK |
| TGP.MGPDP | Case with gold plated bezel and palladium plating | BASE METAL ST.STEEL BACK |
| TGP.MGPHC | SGP bezel, SGP and HC case | BASE METAL ST.STEEL BACK |
| TGP.MGPWD | Case combined with reinforced wood with gold plating | BASE METAL WOOD MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| TGP.MHC | Case gold plated bezel and hard titanium nitride case | BASE METAL ST.STEEL BACK |
| TGP.MHSS | Hard stainless steel with gold plated bezel | ST.STEEL BASE METAL BEZEL |
| TGP.MSSGP | SGP bezel, combined SS and SGP middle | ST.STEEL BASE METAL BEZEL |
| TGP.TIHCCE | SGP bezel, combined TI, HC, and Ceramic one piece case | ST.STEEL SGP + SGP BEZEL |
| TGPCE.MGP | Combined SGP and Ceramic bezel, SGP case | BASE METAL CERAMICS BEZEL |
| TGPDP | Parts of SS plated with gold and palladium plating | ST.STEEL SGP + PDP BEZEL |
| TGPDP.G | Gold plated and palladium plated case | SGP MIDDLE SGP + PDP BEZEL ST.STEEL BACK |
| TGPDP.PD | Gold plated and palladium plated case | PDP MIDDLE SGP + PDP BEZEL ST.STEEL BACK |
| TGPGHA.MGHA | Gold plated case combined with hard material | NICKEL ALLOY MIDDLE BASE METAL + NICKEL ALLOY BEZEL ST.STEEL BACK |
| TGPHSS.MHSS | Case of hard SS with gold plating | ST.STEEL + BASE METAL BEZEL |
| TGPHTI.HTI | Rigid titanium case. (Ti alloy hardness was improved in addition to the characteristics of titanium having excellent lightness, ru corrosion resistance, Hv = 300) case with gold plating | TITANIUM ALLOY BASE METAL + TITANIUM ALLOY BEZEL |
| TGP-MTI | Case combining titanium and gold plated bezel | TITANIUM MIDDLE BASE METAL ST.STEEL BACK |
| TGPSHA.MSHA | Gold plated hard nickel alloy | NICKEL ALLOY MIDDLE BASE METAL + NICKEL ALLOY BEZEL ST.STEEL BACK |
| TGPTI.TI | Combined TI and SGP bezel, TI middle and TI back | TITANIUM + SGP BEZEL |
| THC | Case of SS coated with hard titanium nitride film | ST.STEEL BASE METAL BACK |
| THC.BTI | HC bezel, BTI (Bright Titanium) middle and BTI back | TITANIUM |
| THC.MBCRP | Coating of hard titanium nitride and case subjected to black chrome plating | BASE METAL ST.STEEL BACK |
| THC.MHCPCDP | HC bezel, combined HC and plastic middle with SS back | ST.STEEL + PLASTICS |
| THC.MSHAC | Hard cobalt alloy case subjected to coating of hard titanium nitride, case parts with hard titanium nitride coating | COBALT ALLOY MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| THC.MSSCE | HC bezel, combined SS and Ceramic middle, and SS back | CERAMICS + TITANIUM |
| THC.MTIGLC | Titanium coated with glass (surface hardness is higher than ordinary titanium, Hv = about 350-400) and SS with nitride coating. | TITANIUM MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| THC.TIHCCE | Ceramic Outer Case, TI HC Inner Case | CERAMICS + TITANIUM |
| THCHSS.MHSS | Ferrite hard stainless steel coated with rigid titanium nitride | ST.STEEL ST.STEEL + BASE METAL BEZEL |
| THGC | SS case coated with hard titanium nitride | ST.STEEL BASE METAL BEZEL |
| THGC.MCOAHGC | Cobalt hard alloy case coated with hard nitride | COBALT ALLOY MIDDLE BASE METAL BEZEL ST.STEEL BACK |
| THGC.MHTI | Case combining SS with hard titanium nitride coating on rigid titanium (Rigid Ti = hardness more than ordinary Ti, Hv = about 300) | ST.STEEL + TITAN |
| THGMCETIHG | Combination of titanium and ceramics which was coated with hard titanium nitride | CERAMICS MIDDLE BASE METAL BEZEL TITANIUM BACK |
| THGMCETIHG | HGC bezel, combined Ceramics, TI and HGC middle and combined Ceramics, TI and HGC back | CERAMICS + TITANIUM |
| THGP | Case of SS on which hard gold plating was applied | ST.STEEL HGP BEZEL |
| THTIGP.HTI | Case of hard titanium coated with hard titanium nitride | TITANIUM ALLOY |
| TI | Titanium | TITANIUM |
| TIHC.TI | Case of titanium coated with hard titanium nitride | TITANIUM |
| TIHNT.TI | Titanium case which has been hardened by nitriding treatment. (Hv = about 600, Matte finish) | TITANIUM |
| TPCBCRP.MBCRP | Black chrome plated case combined with plastic. | BASE METAL MIDDLE PLASTICS + BASE METAL BEZEL ST.STEEL BACK |
| TPCFRC.MFRC | Fluorocarbon resin coating was applied and the case combined with plastic | BASE METAL MIDDLE PLASTICS + BASE METAL BEZEL ST.STEEL BACK |
| TPCS | Plastic and SS combined case | ST.STEEL PLASTIC BEZEL |
| TPDP | PDP bezel, SS case | PDP BEZEL + ST.STEEL |
| TPDP.G | Gold plated and palladium plated case | BASE METAL ST.STEEL BACK |
| TPDP.GPD | Gold plated and palladium plated case | BASE METAL ST.STEEL BACK |
| TPDP.MPDPHC | Palladium plating and case coated with rigid titanium | BASE METAL ST.STEEL BACK |
| TSGP | Case of SS plated with gold | ST.STEEL SGP BEZEL |
| TSGP.GPD | Palladium plating and gold plated case | BASE METAL MIDDLE SGP30 BEZEL ST.STEEL BACK |
| TSGP.PD | Gold plated and palladium plated case | PDP MIDDLE SGP BEZEL ST.STEEL BACK |
| TSGP.SSG | Case of SS with gold plating | ST.STEEL+ SGP MIDDLE SGP BEZEL ST.STEEL BACK |
| TSHA | Case combining hard alloy and SS | ST.STEEL NICKEL ALLOY BEZEL |
| TSS.PCA | Case combining SS and plastic | PLASTICS ST.STEEL BACK |
| TSSCE | Combined SS and Ceramic bezel , SS middle and SS back | ST.STEEL ST.STEEL + CERAMIC BEZEL |
| TSSGP | Case of SS with gold plated bezel | ST.STEEL ST.STEEL + SGP BEZEL |
| TSSGP.MGP | Case of SS with gold plated bezel | BASE METAL MIDDLE ST.STEEL + BASE METAL BEZEL ST.STEEL BACK |
| TSSGP.MPDP | Combination of gold plated bezel and palladium plated case | BASE METAL MIDDLE ST.STEEL + BASE METAL BEZEL ST.STEEL BACK |
| TSSHC | SS bezel coated with hard titanium nitride, SS case | ST.STEEL ST.STEEL + BASE METAL BEZEL |
| TSSHC.HICDC | SSHC bezel, SS with super hard coating, and SS with super hard coating back | ST.STEEL ST.STEEL + ST.STEEL BEZEL |
| TTIGLCGP.MTIGLC | Titanium coated with glass (It has a higher surface hardness than ordinary titanium Hv = about 350-400) gold plate applied | TITANIUM MIDDLE TITANIUM + BASE METAL BEZEL ST.STEEL BACK |
| TTIHC.MTIHICDC.TI | Ti & HC bezel, Ti & HC middle, Ti Back | TITANIUM |
| TTIHC.TI | Combined TI and HC bezel, TI middle and TI back | TITANIUM |
| TTUCAC | Hard alloy coated with hard titanium nitride combined with SS case | ST.STEEL TUNGSTEN CARBIDE BEZEL |
| TTUCAC.MGP | Case combining a super hard alloy plated with hard titanium nitride and gold plating | BASE METAL MIDDLE TUNGSTEN CARBIDE BEZEL ST.STEEL BACK |
| TUCAC | Case of the super hard alloy coated with hard titanium nitride (High surface hardness and resistant to small scratches, Hv = about 1200) ** | TUNGSTEN CARBIDE ST.STEEL BACK |
| TUCAC.SSGP | Case combining SS with a gold plate and a hard tungsten alloy coated with a hard titanium nitride | TUNGSTEN CARBIDE + ST.STEEL + BASE METAL ST.STEEL BACK |
| TUCSS | Case combining SS with super hard alloy coated with hard titanium nitride | TUNGSTEN CARBIDE + ST.STEEL ST.STEEL BACK |
| TWGP | White gold plated bezel with stainless steel case | TWGP |
| WGF | White Gold Filled | WGF |
| WGP | White Gold Plating | WGP |
| WGPG | Gold plated case with gold-plated bezel | WGPG |
Old Seiko Watches Value
Note **: Although it is hard to scratch it is slightly brittle so care should be taken to avoid shocks such as a drop.