In the early 1950s, Seiko gradually introduced 5-digit case codes, sometimes preceded by the letter ‘J’. This coding system remained the standard for Seiko watches until 1964, covering a period of just over a decade.
The first two digits of the code approximately indicate the dial size, expressed in lignes. When the first two digits are preceded by the letter ‘J’, it means that half a ligne should be added to the indicated value (for example, J12 corresponds to 12.5 lignes). The remaining three digits represent a progressive number, starting from 000, then 001, 002, and so on.
Seiko J14xxx
| Case Code | Models | Materials |
|---|---|---|
| J14000 | Unique Marvel Laurel Crown | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14001 | Unique Marvel Laurel | Stainless Steel |
| J14002 | Unique | Stainless Steel |
| J14003 | Automatic | 14K Gold Filled |
| J14004 | Marvel Cronos | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14005 | Marvel | Front 14K Gold Filled Steel Back |
| J14006 | Cronos | Stainless Steel |
| J14007 | Marvel | Front 14K Gold Filled Steel Back |
| J14008 | Marvel | Stainless Steel |
| J14009 | Automatic | Stainless Steel |
| J14010 | Marvel | Stainless Steel |
| J14011 | Marvel | Stainless Steel |
| J14012 | Marvel Crown | Stainless Steel, All EGP 20 Microns |
| J14013 | Cronos | Stainless Steel |
| J14014 | Marvel | Stainless Steel |
| J14015 | Automatic | Stainless Steel, 14K Gold Filled |
| J14016 | Cronos | Stainless Steel |
| J14017 | Cronos | Stainless Steel |
| J14018 | Cronos Marvel | Stainless Steel, K18 |
| J14019 | Marvel | Stainless Steel |
| J14020 | Marvel Laurel | Stainless Steel |
| J14021 | Cronos | 14K Gold Filled |
| J14022 | Marvel Laurel Crown | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14023 | Cronos | Stainless Steel |
| J14024 | ? | ? |
| J14025 | ? | ? |
| J14026 | Marvel | Front 14K Gold Filled Steel Back |
| J14027 | Marvel | Front 14K Gold Filled Steel Back |
| J14028 | Cronos | Stainless Steel, Front 14K GF |
| J14029 | Cronos | Stainless Steel |
| J14030 | Automatic | Stainless Steel |
| J14031 | Marvel | Front EGP 20 Microns Back Stainless Steel |
| J14032 | Crown | Stainless Steel |
| J14033 | ? | ? |
| J14034 | Cronos | 18K |
| J14035 | Crown | Stainless Steel |
| J14036 | Crown | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14037 | Super Cronos Champion | Stainless Steel Back, Stainless Steel, Front EGP 20 Microns |
| J14038 | Lord Marvel | Stainless Steel |
| J14039 | Lord Marvel | 14K Gold Filled |
| J14040 | Crown | Stainless Steel, Front 14K GF |
| J14041 | ? | ? |
| J14042 | ? | ? |
| J14043 | ? | ? |
| J14044 | Marvel | Front EGP 20 Microns Back Stainless Steel |
| J14045 | Laurel | Stainless Steel |
| J14046 | ? | ? |
| J14047 | ? | ? |
| J14048 | Cronos | Stainless Steel, Front 14K GF |
| J14049 | ? | ? |
| J14050 | Lord Marvel | 18K Gold |
| J14051 | ? | ? |
| J14052 | ? | ? |
| J14053 | ? | ? |
| J14054 | Gyro Marvel | Stainless Steel, Back Stainless Steel Front EGP 20 Microns |
| J14055 | ? | ? |
| J14056 | ? | ? |
| J14057 | Goldfeather | 14K Gold Filled 80 Microns |
| J14058 | ? | ? |
| J14059 | ? | ? |
| J14060 | Goldfeather | ? |
| J14061 | Cronos | Stainless Steel, 14K Gold Filled |
| J14062 | Gyro Marvel | Stainless Steel, Back Stainless Steel Front EGP 20 Microns |
| J14063 | ? | ? |
| J14064 | Seikomatic | Stainless Steel, All EGP 20 Microns |
| J14065 | Crown Laurel | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14066 | Crown | Stainless Steel, Front EGP 20 Microns |
| J14067 | Liner | Stainless Steel |
| J14068 | Lord Marvel | 14K Gold Filled |
| J14069 | Liner | All Gold Filled |
| J14070 | Grand Seiko Chronometer | 14K Gold Filled |
| J14071 | Crown | ? |
| J14072 | Crown | ? |
| J14073 | Gyro Marvel | ? |
| J14074 | Seikomatic | Stainless Steel, EGP 20 Microns Back Gold Filled |
| J14075 | Seikomatic | Stainless Steel, EGP 20 Microns Back Gold Filled |
| J14076 | ? | ? |
| J14077 | Cronos | Stainless Steel, AEGP |
| J14078 | Goldfeather | 14K Gold Filled |
| J14079 | Crown | Front EGP 20 Microns Back Stainless Steel |
| J14080 | Crown | Front EGP 20 Microns Back Stainless Steel |
| J14081 | ? | ? |
| J14082 | Champion | Stainless Steel |
| J14083 | Cronos | ? |
| J14084 | Crown | Front EGP 20 Microns Back Stainless Steel |
| J14085 | Crown | Stainless Steel, EGP 20 Microns Back Gold Filled |
| J14086 | Liner | Stainless Steel |
| J14087 | Sportsman | Stainless Steel, EGP 20 Microns Back Stainless Steel |
| J14088 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14089 | Crown | Stainless Steel, All EGP 20 Microns |
| J14090 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14091 | Crown | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14092 | Sportsman | Stainless Steel, EGP 20 Microns Back Gold Filled |
| J14093 | ? | ? |
| J14094 | Seikomatic | Stainless Steel, Front EGP 20 Microns |
| J14095 | Crown | Stainless Steel |
| J14096 | Crown | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J14097 | Champion | Stainless Steel |
| J14098 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14099 | Seikomatic | Stainless Steel, All EGP 20 Microns, Front EGP 20 Microns Back Stainless Steel |
| J14100 | Crown Special | All Gold Filled 80 Microns |
| J14101 | Cronos Self Dater | ? |
| J14102 | King Seiko | Stainless Steel, 14K Gold Filled 100 Microns |
| J14103 | Sportsmatic | Stainless Steel, Front EGP 20 Microns |
| J14104 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14105 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14106 | Champion | Stainless Steel, Front EGP 20 Microns |
| J14107 | Cronos (Special Finish) | Stainless Steel |
| J14108 | Motorist (Harmony) | EGP 20 Microns Back Stainless Steel |
| J14109 | Unique | Back Stainless Steel EGP |
| J14110 | Unique Laurel Cronos | Stainless Steel, Back Stainless Steel Front EGP |
Seiko 14xxx
| Case Code | Models | Materials |
|---|---|---|
| 14000 | ? | ? |
| 14001 | ||
| 14002 | ? | ? |
| 14003 | ? | ? |
| 14004 | Super | Back Stainless Steel |
| 14005 | ? | ? |
| 14006 | ? | ? |
| 14007 | ? | ? |
| 14008 | ? | ? |
| 14009 | ? | ? |
| 14010 | Super | Front 14K Gold Filled Steel Back |
| 14011 | ? | ? |
| 14012 | ? | ? |
| 14013 | ? | ? |
| 14014 | ? | ? |
| 14015 | Automatic | 14K Gold Filled |
| 14016 | ? | ? |
| 14017 | ? | ? |
| 14018 | ? | ? |
| 14019 | Marvel | Stainless Steel |
| 14020 | Marvel | Stainless Steel |
| 14021 | Marvel | K14 Gold Filled, Front 14K Gold Filled Steel Back |
| 14022 | Marvel | Front 14K Gold Filled Steel Back |
| 14023 | ? | ? |
| 14024 | ? | ? |
| 14025 | Marvel | Stainless Steel |
| 14026 | Automatic | Stainless Steel |
| 14027 | ? | ? |
| 14028 | ? | ? |
| 14029 | ? | ? |
| 14030 | ? | ? |
| 14031 | ? | ? |
| 14032 | ? | ? |
| 14033 | ? | ? |
| 14034 | ? | ? |
| 14035 | Marvel | Stainless Steel |
| 14036 | ? | ? |
| 14037 | ? | ? |
| 14038 | ? | ? |
| 14039 | Unique | Stainless Steel |
| 14040 | Automatic | 14K Gold Filled |
| 14041 | Marvel Laurel Laurel Alpinist | Stainless Steel |
| 14042 | Unique | ? |
| 14043 | Automatic | Stainless Steel |
| 14044 | ? | ? |
| 14045 | Marvel | Front 14K Gold Filled Steel Back |
| 14046 | Cronos | Stainless Steel |
| 14047 | ? | ? |
| 14048 | ? | ? |
| 14049 | ? | ? |
| 14050 | ? | ? |
| 14051 | ? | ? |
| 14052 | Marvel | Front 14K Gold Filled Stainless Back |
| 14053 | Marvel | ? |
| 14054 | ? | ? |
| 14055 | ? | ? |
| 14056 | Lord Marvel | Stainless Steel |
| 14057 | Lord Marvel | 14K Gold Filled |
| 14058 | ? | ? |
| 14059 | ? | ? |
| 14060 | Automatic | EGP 20 Microns, Stainless Steel |
| 14061 | ? | ? |
| 14062 | ? | ? |
| 14063 | ? | ? |
| 14064 | ? | ? |
| 14065 | ? | ? |
| 14066 | ? | ? |
| 14067 | Automatic | 18K |
| 14068 | ? | ? |
| 14069 | ? | ? |
| 14070 | ? | ? |
| 14071 | ? | ? |
| 14072 | ? | ? |
| 14073 | ? | ? |
| 14074 | ? | ? |
| 14075 | ? | ? |
| 14076 | ? | ? |
| 14077 | ? | ? |
| 14078 | Gyro Marvel | Stainless Steel |
| 14079 | ? | ? |
| 14080 | ? | ? |
| 14081 | ? | ? |
| 14082 | ? | ? |
| 14083 | ? | ? |
| 14084 | ? | ? |
| 14085 | ? | ? |
| 14086 | ? | ? |
| 14087 | ? | ? |
| 14088 | ? | ? |
| 14089 | ? | ? |
| 14090 | Liner | Stainless Steel |
| 14091 | Sportsman | STP |
Seiko J13xxx
| Case Code | Models | Materials |
|---|---|---|
| J13000 | New10 Super Unique Marvel | Stainless Steel, Back Stainless Steel |
| J13001 | New10 Super Unique Marvel | Stainless Steel, Back Stainless Steel |
| J13002 | New10 Super Unique Marvel | Stainless Steel, Back Stainless Steel |
| J13003 | Super Unique Marvel Laurel | Stainless Steel |
| J13004 | ? | ? |
| J13005 | Super Unique Marvel | Stainless Steel, Back Stainless Steel |
| J13006 | Marvel | K18 |
| J13007 | Marvel | Stainless Steel |
| J13008 | ? | ? |
| J13009 | Unique Marvel | Stainless Steel |
| J13010 | Super Marvel | Front 14K Gold Filled Steel Back |
| J13011 | ? | ? |
| J13012 | Super Unique Marvel | Stainless Steel, Back Stainless Steel |
| J13013 | Marvel Laurel Sportsman | Stainless Steel |
| J13014 | Unique Marvel | Stainless Steel |
| J13015 | Unique | Stainless Steel |
| J13016 | Super Marvel Laurel | Back Stainless Steel, Stainless Steel |
| J13017 | Marvel | 14K Gold Filled |
| J13018 | ? | ? |
| J13019 | Super Unique Marvel | Stainless Steel |
| J13020 | Unique Marvel | Stainless Steel |
| J13021 | Marvel | Back Stainless Steel |
| J13022 | Marvel | Stainless Steel |
| J13023 | Super Unique Marvel | Stainless Steel Back, Stainless Steel |
| J13024 | Marvel | Stainless Steel |
| J13025 | Marvel | Stainless Steel |
| J13026 | ? | ? |
| J13027 | ? | ? |
| J13028 | Cronos (Water Proof) | Stainless Steel |
| J13029 | Laurel (Rain Proof) | Stainless Steel |
| J13030 | ? | ? |
| J13031 | Sportsman | Stainless Steel, Front EGP 20 Microns Back Stainless Steel |
| J13032 | Cronos (Water Proof) | Stainless Steel |
| J13033 | Champion Alpinist (Rain Proof) | Stainless Steel |
| J13034 | Seikomatic (Blue Yacht) | Stainless Steel |
| J13035 | Sportsman (Dolphin) | Stainless Steel |
| J13036 | ? | ? |
| J13037 | ? | ? |
| J13038 | ? | ? |
| J13039 | ? | ? |
| J13040 | Champion (Water Proof 30) | Stainless Steel, EGP 20 Microns |
| J13041 | Crown (Water Proof) | Stainless Steel |
| J13042 | Cronos (Water Proof) Champion (Water Proof) | All Stainless Steel, EGP 20 Microns Back Steel |
| J13043 | Champion Alpinist (Water Proof) | Stainless Steel |
| J13044 | Seikomatic (Water Proof 30) | Stainless Steel |
| J13045 | Sportsmatic (Water Proof 30) | Stainless Steel |
| J13046 | Cronos (Water Proof 50) | Stainless Steel |
| J13047 | Champion (Water Proof) | Stainless Steel |
| J13048 | Fairway (Water Proof 30) | EGP STP |
| J13049 | Champion Alpinist (Water Proof) | Stainless Steel |
| J13050 | Champion Calendar (Water Proof) | Stainless Steel |
| J13051 | ? | ? |
| J13052 | Sportsman (Water Proof) | Stainless Steel |
| J13053 | ? | ? |
| J13054 | ? | ? |
| J13055 | Sportsmatic (Water Proof) | Stainless Steel, EGP 20 Microns Back Stainless Steel |
| J13056 | ? | ? |
| J13057 | ? | ? |
| J13058 | ? | ? |
| J13059 | Seikomatic Self Dater (Water Proof 30) | Stainless Steel |
| J13060 | Seikomatic Self Dater (Water Proof 50) | Stainless Steel |
| J13061 | Seikomatic Self Dater | Stainless Steel |
| J13062 | Seikomatic Self Dater | Stainless Steel |
| J13063 | ? | ? |
| J13064 | ? | ? |
| J13065 | ? | ? |
| J13066 | C22 Sea Lion | Stainless Steel |
| J13067 | C22 Sea Lion | Stainless Steel |
| J13068 | ? | ? |
| J13069 | ? | ? |
| J13070 | ? | ? |
| J13071 | ? | ? |
| J13072 | ? | ? |
| J13073 | ? | ? |
| J13074 | ? | ? |
| J13075 | ? | ? |
| J13076 | Champion (Water Proof 30) | All Stainless Steel |
| J13077 | Champion (Water Proof 30) | Stainless Steel, EGP 20 Microns Back Stainless Steel |
| J13078 | Champion Calendar (Water Proof) | Stainless Steel |
| J13079 | Champion Alpinist (Water Proof) | Stainless Steel |
| J13080 | Seikomatic Weekdater (Water Proof 30) | Stainless Steel |
| J13081 | Sportsmatic 5 (Water Proof) | Back Stainless Steel Front EGP, STP |
| J13082 | Sportsman (Water Proof) | Stainless Steel |
| J13083 | Seikomatic Self Dater (Water Proof 70) | Gold Cap 260 Microns |
| J13084 | ? | ? |
| J13085 | Seikomatic Self Dater (Water Proof 50) | Stainless Steel |
| J13086 | C22 Sea Lion (Champion) | Stainless Steel |
| J13087 | C22 Sea Lion (Champion) | Stainless Steel |
| J13088 | M55 Sea Lion (Seikomatic) | Stainless Steel |
Seiko 13xxx
| Case Code | Models | Materials |
|---|---|---|
| 13000 | ? | ? |
| 13001 | New10 | Stainless Steel Back |
| 13002 | ? | ? |
| 13003 | ? | ? |
| 13004 | ? | ? |
| 13005 | Super | Stainless Steel |
| 13006 | ? | ? |
| 13007 | ? | ? |
| 13008 | ? | ? |
| 13009 | ? | ? |
| 13010 | Super | K18 |
| 13011 | Super | Stainless Steel |
| 13012 | ? | ? |
| 13013 | ? | ? |
| 13014 | ? | ? |
| 13015 | ? | ? |
| 13016 | ? | ? |
| 13017 | Super | Top 14k Gold Filled |
| 13018 | ? | ? |
| 13019 | ? | ? |
| 13020 | ? | ? |
| 13021 | ? | ? |
| 13022 | ? | ? |
| 13023 | ? | ? |
| 13024 | Super Marvel | Back Stainless Steel, Stainless Steel |
| 13025 | Super Unique | Back Stainless Steel |
| 13026 | Super Self Dator | Stainless Steel Back, Back Stainless Steel |
| 13027 | ? | ? |
| 13028 | ? | ? |
| 13029 | ? | ? |
| 13030 | ? | ? |
| 13031 | ? | ? |
| 13032 | ? | ? |
| 13033 | Super | Stainless Steel |
| 13034 | ? | ? |
| 13035 | ? | ? |
| 13036 | ? | ? |
| 13037 | ? | ? |
| 13038 | ? | ? |
| 13039 | Super | Stainless Steel |
| 13040 | ? | ? |
| 13041 | Super | Stainless Steel |
| 13042 | ? | ? |
| 13043 | Automatic | Stainless Steel |
| 13044 | ? | ? |
| 13045 | ? | ? |
| 13046 | ? | ? |
| 13047 | New10 Marvel | Stainless Steel Back, Stainless Steel |
| 13048 | ? | ? |
| 13049 | ? | ? |
| 13050 | ? | ? |
| 13051 | ? | ? |
| 13052 | ? | ? |
| 13053 | ? | ? |
| 13054 | ? | ? |
| 13055 | ? | ? |
| 13056 | ? | ? |
| 13057 | ? | ? |
| 13058 | ? | ? |
| 13059 | ? | ? |
| 13060 | ? | ? |
| 13061 | ? | ? |
| 13062 | ? | ? |
| 13063 | ? | ? |
| 13064 | ? | ? |
| 13065 | ? | ? |
| 13066 | ? | ? |
| 13067 | ? | ? |
| 13068 | ? | ? |
| 13069 | ? | ? |
| 13070 | ? | ? |
| 13071 | ? | ? |
| 13072 | ? | ? |
| 13073 | ? | ? |
| 13074 | ? | ? |
| 13075 | ? | ? |
| 13076 | ? | ? |
| 13077 | ? | ? |
| 13078 | ? | ? |
| 13079 | ? | ? |
| 13080 | ? | ? |
| 13081 | ? | ? |
| 13082 | ? | ? |
| 13083 | ? | ? |
| 13084 | ? | ? |
| 13085 | ? | ? |
| 13086 | ? | ? |
| 13087 | ? | ? |
| 13088 | ? | ? |
Seiko J12xxx
| Case Code | Models | Materials |
|---|---|---|
| J12000 | ? | ? |
| J12001 | ? | ? |
| J12002 | ? | ? |
| J12003 | ? | ? |
| J12004 | ? | ? |
| J12005 | ? | ? |
| J12006 | ? | ? |
| J12007 | ? | ? |
| J12008 | ? | ? |
| J12009 | ? | ? |
| J12010 | ? | ? |
| J12011 | ? | ? |
| J12012 | ? | ? |
| J12013 | ? | ? |
| J12014 | ? | ? |
| J12015 | ? | ? |
| J12016 | ? | ? |
| J12017 | ? | ? |
| J12018 | ? | ? |
| J12019 | ? | ? |
| J12020 | ? | ? |
| J12021 | ? | ? |
| J12022 | ? | ? |
| J12023 | ? | ? |
| J12024 | ? | ? |
| J12025 | ? | ? |
| J12026 | ? | ? |
| J12027 | ? | ? |
| J12028 | ? | ? |
| J12029 | ? | ? |
| J12030 | ? | ? |
| J12031 | ? | ? |
| J12032 | Seikomatic SilverWave (Water Proof 30) | Stainless Steel |
| J12033 | ? | ? |
| J12034 | ? | ? |
| J12035 | ? | ? |
| J12036 | ? | ? |
| J12037 | ? | ? |
| J12038 | ? | ? |
| J12039 | ? | ? |
| J12040 | ? | ? |
| J12041 | ? | ? |
| J12042 | ? | ? |
| J12043 | ? | ? |
| J12044 | ? | ? |
| J12045 | ? | ? |
| J12046 | ? | ? |
| J12047 | ? | ? |
| J12048 | ? | ? |
| J12049 | ? | ? |
| J12050 | ? | ? |
| J12051 | ? | ? |
| J12052 | ? | ? |
| J12053 | ? | ? |
| J12054 | ? | ? |
| J12055 | ? | ? |
| J12056 | ? | ? |
| J12057 | ? | ? |
| J12058 | ? | ? |
| J12059 | ? | ? |
| J12060 | ? | ? |
| J12061 | ? | ? |
| J12062 | ? | ? |
| J12063 | ? | ? |
| J12064 | ? | ? |
| J12065 | ? | ? |
| J12066 | ? | ? |
| J12067 | ? | ? |
| J12068 | ? | ? |
| J12069 | ? | ? |
| J12070 | ? | ? |
| J12071 | ? | ? |
| J12072 | ? | ? |
| J12073 | ? | ? |
| J12074 | ? | ? |
| J12075 | ? | ? |
| J12076 | ? | ? |
| J12077 | ? | ? |
| J12078 | ? | ? |
| J12079 | ? | ? |
| J12080 | Liner | Stainless Steel |
| J12081 | Goldfeather | EGP 20 Microns |
| J12082 | Seikomatic SilverWave (Water Proof 50) | Stainless Steel |
| J12083 | ? | ? |
| J12084 | Disney Time | Back Stainless Steel |
| J12085 | ? | ? |
| J12086 | ? | ? |
| J12087 | ? | ? |
| J12088 | ? | ? |