Cal. 8L35 is an automatic watch movement with date produced by Seiko’s Shizukuichi Watch Studio for the Brightz and Prospex brands starting 2001 and remains in production as of 2020. It was based on the Grand Seiko Cal. 9S55 which was produced at the same time but has been phased out since 2010. The Brightz Cal. 8L21 was similar but lacks the date complication.
Cal. 8L35 was first used in the Prospex Marine Master Pro SBDX line in 2000 and remains in use as of 2020. Note that the Prospex SLA is simply a different model numbering system and these watches also have SBDX numbers. From 2010 through 2013 it was also used in the Brightz Phoenix SAGQ model line.
| Production | Application | Winding | Jewels | Notes | |
|---|---|---|---|---|---|
| 8L21 | 2003-2007 | Brightz SAGL | Automatic | 24 | Similar to 9S51 |
| 8L34 | 2000 | Railway pocket watch | Manual | 20 | Small seconds |
| 8L35 | 2000-present | Brightz SAGQ Prospex SBDX Prospex SLA | Automatic | 26 | Date, similar to 9S55 |
| 8L36 | 2011-present | Credor GCBZ Galante SBLM | Automatic | 27 | GMT, similar to 9S56 |
| 8L38 | 2010-2015 | Galante SBLL | Automatic | 26 | Open Heart |
| 8L75 | -2005 | Credor GCBR | Automatic | 26 | Date, similar to 9S55 |
| 9S51 | 1998-2009 | GS SBGR | Automatic | 24 | No date |
| 9S54 | 2001-2010 | GS SBGW | Manual | 20 | No date |
| 9S55 | 1998-2010 | GS SBGR | Automatic | 26 | Date |
| 9S56 | 2002-2010 | GS SBGM | Automatic | 27 | GMT, no date |