Sinn 356 Flieger

I have always been attracted to military type watches but I will openly admit that as little as six or seven years ago I didn’t know where any such thing could be found – either real or pseudo. The year 2000 and military styled watches abound; the Internet has enabled those in far flung places access to watches that they might not have known even existed; even better, the Internet has made access to such watches relatively easy.

I first learned of the existence of Sinn some four years ago whilst living in South East Asia; a friend and highly respected member of TZ tried in vain to order one for me – in the end I think we both gave up on it. I still hankered after a Sinn and on returning to the UK managed to buy a 144GMT – a monster of a watch and great value for money. That one came and went and now I find myself the proud owner of a 356 Flieger which has turned out to be my everyday watch.

Sinn 356 Flieger


The 356 has evolved out of a limited edition watch for the Japanese market which I believe dates back to 1996. It is a plain, no nonsense military/pilot’s styled watch. This is clearly demonstrated by the matt finished case, the matt black dial and the large Arabic numerals which are matched by the white hands and chronograph pointers. Sinn is a specialist in tool watches and the 356 doesn’t stray from this philosophy – personally I like a watch that I can see easily, I can wear if I swim and that I can use to time events if necessary.

The 356 does it all and makes no pretensions to be anything other than functional. This functionality is aided by the use of the almost statutory Valjoux 7750 chronograph calibre (now from ETA) which itself is generally considered to be a rugged and reliable unit though not without its problems. The 356 in more detail…

The Case

The 356 features a matt finished stainless steel case which some refer to as sandblasted or beadblasted; this is in true military style and serves to cut down on glare; furthermore it may also serve to artificially harden the steel due to the compressive effect of the blasting process. I feel that this hardening effect would possibly be directly proportional to the technique used to produce the case finish. That being said, the matt finish suits the watch perfectly and it appears to be well executed.

The case itself is 38.5mm in diameter excluding the crown; the bezel is integral to the case top and the distance between the lugs is 20mm. Case thickness is 14mm. The profile of the watch I find particularly pleasing with a curve to the lugs which again smacks of old military favourites:

Sinn 356

The picture shows this curvature along with the protective shoulders for the winding crown which screws down snugly and contributes no doubt to the 100m water resistance rating. The chronograph pushers feature fixed rings which serve to some degree as protection but once again give the watch a rugged and businesslike look.

The screw case back is signed Sinn, features a unique serial number along with indications in German that the watch is steel, shock resistant, anti-magnetic and water resistant to 10 Bar. It is also bowl shaped which reduces the area in contact with the wrist and in my experience makes the watch very comfortable to wear. This advantage is in my case negated slightly by the fact that I now wear the 356 on a NATO strap; a personal preference but in my opinion, well in keeping with the overall theme of the watch.

In general, the case appears to be well cut; the inner lug surfaces are straight and parallel, there are no sharp edges and the lug ends are very slightly rounded, thus they won’t dig into wrists. The key slots for opening the case back are of the half moon variety so opening the case without the correct tool would more than likely cause unsightly damage.

Dial, Hands and Crystal

The dial of the 356, as previously mentioned is without doubt very functional. It is designed to help the wearer see the time at a glance and to be able to take chronograph readings in the same manner. The whole of the dial is matt black. The outer minute markers and five minute markers are in white and are non-luminous. Likewise the chronograph dials with their respective scales are also in non-luminous white. Application of the white paint to the dial is acceptable; under a 10x loupe things are a little different and there is a certain roughness to the application. This in no way detracts from the watch under normal circumstances and I mention it as a matter of course; everyday wear and it would be extremely difficult to notice. The dial is signed Sinn and Flieger and that’s it – no extraneous references to anything else and I have to admit that this is the way I like it – pure and simple.

Sinn 356 Dial

The Arabic numerals are coated in a non-radioactive compound which I am assuming to be of the Luminova variety. No longer does the 356 show letter T’s at the bottom of the dial.

Application of this compound is thick and even and it does the job well. After exposure to bright light for a few minutes, I can read the time after seven or eight hours of darkness.

The glossy white painted hour and minute hands also feature a good fill of luminous compound and pleasingly, they glow to the same extent and for the same period as the numerals. All chronograph hands are painted glossy white.

Finally, the chronograph centre second hand features a luminous diamond which certainly looks pretty at night and helps one to ascertain where the twelve should be! In low/partial light conditions this watch is superb and wins hands down over Tritium:

Sinn 356 Luminosity

Again in military fashion, the 356 features a domed acrylic crystal. A matt black tension ring helps hold this in place and I feel that black was an excellent choice, matching the dial perfectly. Personally I like the acrylic crystal. It gives the watch character in terms of its profile, glare is not a major problem and it is difficult to shatter. A flat crystal would ruin this watch for me as would a mineral crystal with the inherent problems of scratch removal.

OK, so acrylic scratches even when you look at it, but a little Brasso or even toothpaste(!) and all’s well within a couple of minutes. Again, from a personal perspective I find that an acrylic crystal seems to help a watch age gracefully; as the watch becomes scratched and chipped and takes on character then the acrylic crystal does so too. To me, a ten year old watch with a perfect sapphire crystal looks odd somehow.

The Movement

A standard Valjoux 7750 automatic (winding in one direction of the rotor) chronograph movement is utilised in the 356. This calibre beats at 28,800 bph, has 25 jewels and features day and date indication which can be quick-set. Normally, the day indication is in German but a little patience and Sinn will provide an English day if you so desire.

The unscrewed position of the crown allows the watch to be hand wound; the second position and the day and date can be quick-set: turn the crown one way to advance the date and the other way to advance the day (actually the day doesn’t advance as such – it retreats). The final position of the crown stops the seconds for exact time-setting and allows the hands to be set. Some practice is required to synchronise the minute hand with the seconds, I usually set the minute hand about twenty seconds ahead as it were and this normally allows for the slack in the movement.

The chronograph functions are standard with central seconds, a minute recorder at twelve and an hour recorder at six. The two o’clock button starts and stops the chronograph and the four o’clock button resets to zero. I have had no problems with the chronograph; it operates smoothly with everything resetting as it should. Constant (normal timekeeping) seconds are at nine o’clock.

For me, timekeeping has been excellent and this example runs consistently at +3 seconds per day, well within COSC specs and certainly accurate enough for me. I have been told by Sinn in the past that their normal specification for timekeeping is no more than +10 seconds per day. Maybe I was lucky but I have heard other reports of phenomenal accuracy from standard Sinn timepieces.

The day and date start to change gradually at around 11.10 with the date jumping at 11.57 and the day following at around 12.10. If ever the date needs to be quick-set I am especially careful, I have heard horror stories of the damage done to 7750’s if quick-setting is performed during the prohibited hours!

Overall I feel that the 7750 suits the watch well; from a real chronograph user’s perspective though things may be a little different. Many people would possibly prefer to see the use of the Lemania 5100 in this watch given that it has both central seconds and minutes for the chronograph and is thus possibly easier to read when timings are critical. What mustn’t be forgotten in this case though is the value that this watch represents; use of the Lemania could add significantly to the price, taking the 356 out of what I feel to be a bargain bracket. As it is, I am happy with the performance and reliability of the 7750 in my example.

The Strap

Standard issue for the 356 is a black leather strap with a signed buckle in matt steel. A bracelet is also available but I do not feel that it suits the watch well given the relatively narrow lugs and 20mm gap between them.

The leather is of decent quality and comfortable with some padding but I couldn’t wait to replace it with the NATO nylon strap. For me this just finishes the watch off. I know that the NATO’s are an acquired taste to some degree but from a functional perspective and for the way I wear the 356 then they cannot be beaten. If one spring bar should pop then I won’t lose my watch, I can swim with this strap, shower with it..whatever. I also think that the NATO suits the watch – but that’s just me!


Sinn 356 Flieger

As an everyday watch, to do anything and go anywhere I would find it hard to better the Sinn 356. For its price it represents excellent value for money in my opinion. This style of watch is not to everybody’s taste but for those who like the military look and simple functionality I would not hesitate in recommending it. Whilst the advantages of this watch I hope have been outlined above, what are the possible downsides?

If you insist on factory service you could wait a long time to get your watch back – but this is a stock movement so theoretically factory service isn’t essential. The matt finish of the case is very apt for this watch – but scratch it, dent it and scrape it and save for specialist refinishing, that pretty much is that; you’ll need to live with it. If the crystal gets cracked will the watch need factory service? This one I can’t answer, maybe a stock crystal is available? For me, they are the potential downsides of this watch but I can live with them!

For UK readers who wish to purchase this, or any other Sinn watch, I can highly recommend Neil Wood at Chronomaster who provides a courteous and efficient service; follow the link to his Sinn page: Sinn Uhren at Chronomaster

Thanks for reading this; I hope you enjoyed it and please bear in mind that all the contents are just my opinion based on my experiences.

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