The BA111OD CHPTR_Δ is hypocycloidal genius personified The BA111OD CHPTR_Δ is hypocycloidal genius personified

The BA111OD CHPTR_Δ is hypocycloidal genius personified

Fergus Nash
  • The new BA111OD CHPTR_Δ introduces hypocycloidal time-telling.
  • Olivier Mory, who built the cheapest Swiss-made tourbillon, was involved with the in-house BA111LOD 09310 module.
  • For only US$2,620, it’s an incredible value proposition for a technical Swiss luxury watch.

BA111OD have only been around since 2019, but there seems to be no limit to their ambition of disrupting the industry. If you’re in the market for a luxury Swiss watch with an in-house movement of unique complexity, then chances are you’re looking at spending at least five figures. The BA111OD CHPTR_Δ provides all of that and more, but for the same price as a mid-tier Longines. With the founder Thomas Baillod’s dedication to working with Swiss manufacturers and watchmaker Olivier Mory’s inventiveness to overcome limitation, the BA111OD CHPTR_Δ would be an amazing contemporary addition to any collection.


At first glance the main display of the BA111OD CHPTR_Δ (pronounced as Chapter Delta) looks similar to an Urwerk style of displaying the time, however that could not be further from the case. While the minute hand traverses the dial as usual, the hours are indicated by the journey of a satellite dot. Achieving a triangle-shaped path for this display requires a deep understanding of mathematics and geometry, and with words such as ‘hypocycloidal’ being thrown around it can be easy to get overwhelmed. The BA111OD-manufactured movement is called the module 09310, and it is based on the Soprod M100.


Launched just before Watches & Wonders 2023, there are three versions of the BA111OD CHPTR_Δ with slightly varying colour schemes. The CHPTR_Δ.1 features a grey backdrop with a deep blue dot, the CHPTR_Δ.2 is black with a red dot, and the CHPTR_Δ.3 pairs blue tones with a bright yellow dot. The architectural design of the watch’s dial is truly captivating, yet again proving that BA111OD’s collective talent is well above their price point. The 44mm case is made of stainless steel with wrist-friendly short lugs to ground the watch somewhat, although its wrist presence is always going to be impressive.

The BA111OD CHPTR_Δ pricing and availability:

The BA111OD CHPTR_Δ is available now from their website. Price: US$2,620

Brand BA111OD
Case Dimensions 44mm
Case Material Stainless steel
Water Resistance 5om
Crystal(s) Sapphire with NFC tag technology
Dial Grey, black, or blue
Strap Rubber with quick-release
Movement BA111OD-manufactured module 09310 with hypocycloidal time display
Power Reserve 42 hours
Availability Available now
Price US$2,620