Any F. P. Journe enthusiast knows about the superb gold movement the brand creates. Some are also aware that originally (until 2004) the brand employed brass movements instead of gold. Few however are aware of the "ruthenium series".

When F. P. Journe decided to switch to gold movements, the 99 final pieces of the 5 Journe calibres in production were coated in ruthenium, an element known for its extreme hardness and chemical inertia. The same process was applied to the dials as well, and thus the "Ruthenium Series" were born.

The 5 watches that are part of the collection, beyond this model, are the Tourbillon Souverain, the Chronomètre à Résonance, the Octa Calendrier and the Octa Chronograph. All these models are ruthenium coated counterparts to their brass piers. The present Octa Réserve de Marche Jour et Nuit model has however a different story to tell. It is the only model from the Ruthenium Series which is unique, without a "standard" brass counterpart. The cal. 1300, which powers it, is also present in the Octa Réserve de Marche, but without the day/night indicator: a detail present exclusively on the Ruthenium Series. It is unknown why Mr. Journe decided to upgrade exclusively cal. 1300, leaving the other 4 untouched. What is certain is that the fact that this is the only F.P. Journe piece which is singular to the Ruthenium Series enormously amplifies the importance and collectability of this watch, which is furthermore the fifth-last one to leave the factory, bearing number 95/99.