The 6119 are derivated from the 6106, but slightly simplified in favor of lowest cost (as the lesser number of rubies and the withdrawal of hack), thus being able to equip a bigger number of basic models. But they are practically identical.

    As much the 6106 how much the 6119 had been launched in 3 revisions, A, B and C. In both 6106 and 6119, the first version have the rotor fixed by two screws. In revision "B", the rotor become fixed by an only central screw. In revision "C", they had the bilingual calendar introduced and the adjustment of the day (of the week) also started to be by pressing the crown. In the revisions "A" and "the B", the calendar was in one language, and only the date (day of the month) could be adjusted pressing the crown, while the adjustment of the day was done by "back and for" of the hands. By the way, this adjustment of the calendar was a very confortable function, present in almost all the line 61xx. Also, it was a simpler solution, from a technical point of view, in comparison to the adjustment by turning the crown.
  
    The 6119 are more known and gained bigger fame than the 6106 mainly for having equipped more basic models, in contrast of the 6106, that was more destined to the luxury models, as the Seiko 5 DX and Seiko 5 ACTUS. The large diameter balance wheel offers good rate stability. The 6119 are easy to be adjusted and regulated for good accuracy. The use of the Diafix in the escape wheel also contributes in the precision. The simplicity of the calibre as a whole made it one of the easiest movements to repair. The watchmakers commonlly praise this calibre for its easiness for repairing, the easiness to adjust and to regulate for a good precision, and its robustness.

    The 61xx line also have variants endowed with complications, as GMT function in calibre 6117, that it equips the "World Time" and "Navigator Timer" models, and the famous chronographs with column wheel 6139 and 6138, that are considered, without doubt, "high-end" calibres. The 6139 were launched in 1969, and, although not have been the first automatic chronograph to be presented in history, he was the first one to be in the stores, available for the consumers, in May 1969. Therefore some mention the Seiko and its 6139 in the history of the race for the first automatic chronograph. Moreover, the 6139 presented a new coupling system developed and patented by Seiko.

    More than that, the 61xx line counts on its nobler variants equipping the Grand Seiko collection. The quality in the design of this line allowed to the creation of the excellent calibre 6145 (25 jewels, date, Hi-Beat 36,000 bph) and derivatives, all Hi-Beat, to equip the Grand Seiko 61GS, that is considered one of best Grand Seiko (losing only for the 45GS), having versions with three levels of certification. The "GS Standard", less rigorous certificate (calibres 6145 and 6146), the "GS Special", more rigorous (calibres 6155 and 6156) and the "top", known as "GS V.F.A." (Very Fine Adjustment). These last ones, equipped with calibres 6185 and 6186, were produced and adjusted by the most qualified engineers of the company, and only with parts selected through a rigorous process. They were guaranteed for an average rate of +60 s/month.

    In 1969, Seiko, through the Daini Seikosha, presented calibre 7005, that brought a new automatic winding design. Its intention was to make a movement with a more rational arrangement, to reach a more stable functioning, and facilitating to the dismount and assembly. As result, the number of parts, screws and springs was reduced, also diminishing the number of focus of possible imperfections. For such result, the automatic system was one that suffered greater alterations, bringing a new concept. A thinner movement also was obtained with the new arrangement of the system of the automatic winding.  As comparison, the 6119 have 5,15 mm of height, while the 7005 have 4,50 mm, less than ETA 2824 that it have 4,60 mm (5,05 mm for the 2836).

    The second generation was developed with the addition of the bilingual calendar and the calendar quick-set of the day of the week pressing the crown. These innovations had appeared in calibre 7019. The 7019 is slightly more sophisticated compared to the majority of the 70xx line, equipping the collections "Seiko 5 Actus" and "5 Seiko Advan".

    The adjustment of the calendar pressing the crown was abandoned in the third generation, when 7009 had appeared (17 jewels, day and date) and 7002 (17 jewels, date). They did not bring practically no great newness. As much 7002 and 7009, as 7S26, are 4,90 mm high.

    Still thus, the use of the Magic-lever system is capable of a more efficient winding than the known swiss "Eterna" system, and others that use gears.

    The non modular construction have another inconvenience, that makes with that everything is on to the top plate, needing its dismount to removal of the transmission wheel, that is hold in place through a "C-Ring", a small ring in a "C" shape, under the plate.

    Moreover, this system requires a special adjustment at the moment of assembly. The reduction wheel has a marking that need to coincide with another marking in the rotor, therefore the eccentric axle (as all eccentric axle) where the Magic-lever is mounted has a shorter movement in one determined position, and the movement is gradually becoming ampler as the axle turns, until reaching a maximum point. From there, the amplitude of this movement gradually goes diminishing until a minimum point and this cycle repeats. This adjustment serves to prevent the shorter point of movement coincides with the position where the watch is more used (in the left arm, stand foot or seated). If mounted on a wrong way, the efficiency can be well reduced. In the line 61xx, the axle (or pin) is in the rotor, and thus it already was manufactured in the ideal position, excusing adjustment.

    Other technical aspects differentiate the 70xx from 61xx line, as the reduced diameter of the balance wheel and the quick-set of the calendar. In all 70xx line, the balance wheel is smaller, that theoretically is less steady, and confers greater difficulty of adjustment for good precision. In its majority, the 70xx line does not have adjustment of the calendar by pressing the crown (present on the entire 61xx family), that is a simpler system and more confortable.

    The 70xx line was designed with the intention of being a second option of movement for the main segment of Seiko. With the sprouting of quartz, the mechanical movements production and development was clearly in second plain. Practically only the 70xx line was continued in the 80's.

    In 1976 Seiko launched the 63xx line of calibres. Also designed by Suwa Seikosha, 63xx was a kind of modernization of the 61xx line, keeping the old, however practical, efficient and trustworthy modular automatic winding system. It also kept the larger balance wheel and its characteristic stability. A curiosity of the line 63xx was the moon-phase in calibre 6347.

    The biggest difference in the line 63xx, compared with 61xx, was the calendar system, that started to adopt adjustment turning the crown, instead of pressing it, and also it started to adopt more plastic parts, as the calendar wheel. The line also presented a new system of setting of the hairspring in the regulator, promising geater easiness in the maintenance. But they are practically identical lines, keeping the same quality and trustworthiness of the 61xx line. Half of the parts, or more, is interchangeable with the 61xx line. But the 63xx line ended being little developed and little used. Although calibre 6309 remained for more time, equipping the Seiko Divers 150m since 1976 up to 1988, in the traditional collections Seiko preferred to keep the 70xx line, by practically all the 80's and 90's decades, with only two calibres, 7009 and 7002.

    Today, in the regular mechanical line, it only has 7S26 calibre and variants (7S25, 7S35 and 7S36, and 7S55). However, there are "high-end" mechanical calibres equipping the Grand Seiko, and the Credor and Brightz lines.




Seiko Military 7S26


    The 61xx and 70xx lines demonstrate the capacity of Suwa and Daini to produce equivalent results, as the known trustworthiness, translated robustness and precision, using different solutions of design. However, keeping a basic concept: simplicity.

    In the practice, for the user, the biggest differences are the fact of the winding of 70xx is a little less efficient, and also the fact it is not so easy to be adjusted and regulated as 61xx. But also it is necessary to take in account the technical aspects that do not make direct difference for the user, as the easiness to work on the modular construction of the automatic system in 61xx, from the point of view of the maintenance.

    The summary of the comparison is that 70xx is a little behind the 61xx line regarding winding efficiency, accuracy, and maintenance easiness.