For the past 10 years, the Sarpaneva workshop in Helsinki has been creating a name for itself producing unusual, limited series of watches – exclusively in different types of steel. Now, the Finnish watchmaker is presenting timepieces made of gold.
However, this didn’t mean that the new KORONA would simply be the same watchcase, merely in gold. Stepan took the decision to review the design; the case, with its slightly smaller 42 mm diameter compared to the previous KORONA K3 models of 44 mm, is just right for today’s tastes.
The evocative scallops that are such a part of the exterior edges visual look are now cut right through the case from front bezel to back bezel, making the case even more distinctive. This, in combination with the skeleton dial has the effect of making the watch appear bolder and more uniquely Finnish in its design imagery, without it being perceived as either too large or too small.
The Moonphase indicator of the KORONA RG and WG, with its eternally somber face has become a hallmark of the entire series of KORONA watches,
Creating these Moonphase discs is as complex as the realization of the watch’s Moonphase mechanism. The first dilemma concerns the dimensions, as the face is only 0.4 mm thick yet contains four levels of elevation.
The first step requires creating a drawing six times actual size, followed by cutting a rough model from plate stock, one piece corresponding to each level of elevation of the oversized model. These parts are then fixed together to form the model plate for the pantograph, which will mill the various shapes into a small piece of copper the actual size of the Moonphase.
This copper version, which will serve later as an electrode, is then cleaned up and ‘fine-tuned’ by a master engraver before the contours are electro etched into a steel-pressing block, thus creating a negative image of the face. Last but not least, the eyes are modeled by hand into the negative image and the whole is finished by a master engraver and diamond polished before undergoing hardening, followed by yet another polishing.
The Moonphase of the watch requires two of these Moon faces to be created, but the winding rotor, responsible for helping automatically wind the watch with each movement of the wearer’s arm, also needed special treatment in order to be in harmony with the dial side view.
The skeletonized dial and rotor in every KORONA RG and WG look so simple that one can easily forget the amount of work involved in producing them. Once the dial and rotor have been correctly sized in all dimensions, 260 individual holes need to be cut out of the dial, whose thickness is 0.3 millimeter. After this, each individual hole must be filed and finished, from both sides, therefore even the side that you will never see.
The production of a completely assembled skeletonized dial and rotor, with all the additional parts and Moon faces installed takes a total of about a week of work to complete.
The watch’s base caliber is a new independent movement from the well-known and highly regarded Swiss manufactory Soprod SA. The base caliber is then further modified at the Sarpaneva workshop and fitted with new parts, all of which are manufactured in Finland.
The entire movement is also re-finished, starting from the main plate, which receives gilding after hand finishing. The entire Moonphase mechanism gearing and parts are all designed and made in Helsinki as well. It includes quite a few parts with very small tolerances to insure perfect functioning, the smallest of which being only 0.15 mm thickness.
Different from other Moonphase calibers, the Sarpaneva design features correction via the crown, thus eliminating the need for any pushers on the case, greatly simplifying any correction if necessary. However, it should be noted that if the watch is regularly wound, the next correction for the Moonphase would only be in another 122 years.
For the new gold watches a special presentation box was designed and created by Stepan Sarpaneva, and is also manufactured in Finland. This wood and aluminum creation, embodying all the stylistic directness and raw energy of the timepieces, are also made by hand in small numbers that follow the limited production of the KORONA.
An instruction booklet and guarantee certificate is included with each timepiece, covering a guarantee period of two years from the date of purchase.