Two automatic watches with high-frequency movements, the Seiko Grand Seiko Hi-Beat 36000 and Zenith Espada, square off in a battle of the fast-beat balances in this feature from the WatchTime archives.
A fast-beat movement offers an advantage over its lower-frequency rivals: more beats per hour means greater precision. The principle is simple: the accuracy with which time can be measured and displayed is inversely proportional to the size of the units into which it is divided. Fast-beat movements are also more shock-resistant than slower-beat ones, and this is an added boon to precision. Two companies make series-produced movements with frequencies of 36,000 vph. One is Zenith; the other is Seiko. We tested one watch from each brand to find out how they measure up against each other in terms of precision and a host of other criteria.
The Zenith watch, called the Espada, is equipped with a modified version of the company’s celebrated El Primero movement. In its “natural” form, the El Primero is, of course, a chronograph movement. To make the Espada’s movement, a three-hand automatic caliber called the El Primero 4650B, Zenith removed the chronograph mechanism from the El Primero. The Seiko watch, called the Grand Seiko Hi-Beat 36000, contains the automatic Caliber 9S85, introduced in 2009. Both movements required much work to develop. Modifying the El Primero chronograph caliber to power a three-handed watch involved more than merely reducing the number of parts from 280 to 210. The stopwatch mechanism was removed, but it was partly reinstalled afterward. The bridges had to be redesigned and the continually running seconds hand relocated from an off-center subdial to the center of the dial. The resulting construction resembles the classic pattern of a basic caliber in which the central seconds hand is positioned directly within the flow of force rather than drawing its power from a rudiment left over from the chronograph mechanism.
Seiko faced its own challenges. It spent five years developing a special alloy, Spron 610, for its caliber’s hairspring (Seiko makes its own hairsprings and mainsprings). Spron 610 has greater resistance to shocks and magnetism than standard alloys. Because a high frequency puts additional stress on the movement, Seiko redesigned the lever, escape wheel and pallets to increase their longevity. It developed another alloy, Spron 530, for use in the caliber’s mainspring. Spron 530 enables the spring to withstand the stronger torque required by the high-frequency balance: the torque in five-hertz Caliber 9S85 is twice as high as in Seiko’s four-hertz calibers. The spring provides an impressive power reserve of 55 hours.
Zenith did not add a stop-seconds function when it modified the El Primero movement. You might ask what the point is of having an extremely precise movement in a plain automatic watch, with no chronograph, if you can’t set the watch with to-the-second accuracy. We tried using an old trick to stop the seconds hand: pulling the crown out to the hand-setting position and then gently turning it counterclockwise. It didn’t work. The seconds hand had so much play that it jumped backward a full five seconds. Seiko’s watch does have a stop-seconds function. El Primero 4650B’s amplitudes are quite low, something you’d be more likely to find in a movement that was carrying the extra burden of powering a chronograph mechanism. This initially led us to suspect that there’s merely a gear train connected to the central seconds hand (formerly the elapsed-seconds hand) from the former off-center seconds hand. But we found this is not the case, so the amplitudes must result from the overall configuration of the movement. However, they don’t hurt the movement’s rate. The amplitudes of Seiko’s Caliber 9S85, on the other hand, are in the usual and expected range.
Both timepieces delivered good rate behavior. Zenith’s model always remained on the “gain” side of zero: it never lost time, and it exhibited this fine performance in all situations: fully wound, after running for 24 hours, and on the wrist. Seiko’s watch ran better, but it strayed into the “minus” column in several positions. It scored a perfect “zero” in the “average daily rate” category when we crunched the numbers, but it lost a bit of time after running for a day – a shortcoming that horological sticklers would find worthy of criticism. On the other hand, we were pleased to see that it ran well in the “plus” column on the wrist. Although the watches aren’t officially certified by COSC, both met not only COSC standards, but the slightly more stringent standards of Seiko’s own Grand Seiko Inspection Standard.
Five screws hold a window of sapphire in the back of the Espada, enabling us to see the new and compact bridge for the automatic-winding mechanism. The mechanism partially obstructed our view of the escapement and the polarizing train for the rotor, which winds the mainspring in both directions of rotation. Although our view was also blocked by the circularly grained bridge, there’s a large bridge beneath it: this construction comes from the former El Primero and covers the entire movement like a three-quarters plate. Stripping El Primero down to serve as a movement for a three-handed watch robs it of its chronograph architecture, but the movement still speaks Zenith’s language, thanks to the brand’s star-shaped logo cut in openwork into the rotor, the fine adjustment via an eccentric screw on an elongated regulator arm and, of course, the fast-paced balance. Seiko’s caliber 9S85 also makes a brand-specific statement behind a screwed-down window of sapphire in its caseback. Seiko fans will recognize the company’s trademark wavy embellishments, similar to Geneva waves, which decorate the bridges, the cocks and the slightly skeletonized rotor. Like the rotor on the Zenith movement, Seiko’s rotor winds the mainspring in both directions of rotation. Seiko uses its well-known Magic Lever pawl indexing system, which it introduced in 1959. The Magic Lever system increases the transfer of power to the mainspring and delivers faster winding speed by harnessing all the energy created by the rotor as it revolves in both directions.
We were disappointed to find that the Magic Lever is hidden from view by the bridge of the movement. Due to the caliber’s bridge construction, you can’t see much more of the 9S85 than you can of Zenith’s movement. Fine adjustment of the balance (which is also manufactured by Seiko) occurs via an eccentric screw (as it does in El Primero), but Seiko’s eccentric screw is paired with a much shorter regulator arm. The name “Grand Seiko” is engraved on the winding rotor in bold letters that are inlaid with gold. When you look at the Grand Seiko’s case, its elegance, functional details and high-quality craftsmanship can be seen from all angles, whether you gaze downward at the steeply sloped and polished bezel, look from the front at the stylized lugs or peer from the side at the arches of the case’s middle section. Like the movement, the case and bracelet are manufactured by Seiko. The processing lavished on the case is especially noteworthy: zaratsu, or “blade polishing,” is accomplished by holding the case against a rotating tin plate at a very precise angle. This creates a mirror finish on both sides of the case, as well as fine bevels on the lugs.
The Grand Seiko’s three-part stainless-steel bracelet (like CITIZEN ECO DRIVE RADIO CONTROLLED ) is also partly polished and partly matte finished. It is solid but lightweight. It feels supple and harmonizes with the curved middle section of the case to wrap comfortably around its wearer’s wrist. The size differences in the links of the bracelet, which tapers slightly from the lugs to the clasp, add to the harmony. The single-folding clasp closes smoothly. It opens easily when its lateral buttons are pressed. Several links in the bracelet are screwed on either side of the clasp so the bracelet can be easily lengthened or shortened.
