Seiko

 

< When you start/stop the chronograph, the small-seconds hand in the subdial at 3 will jump and stutter >

 

When I inquired with GS, they formally advised me that they neither can fix the issue nor consider it a problem (in their words, the stutter jump is a “characteristic” of the movement).    

 

Before buying, be sure to check and see for yourselves in order to see if you can live with the issue or quirk, as ymmv.

Personally, I found the issue in the fairly new, highly (GS) touted movement and relatively pricey line of watches unacceptable.

Images from the Net

Im a huge fan of Grand Seiko and was similarly excited for their 9SA5 movement. Technically very impressive but the fact of the matter is it simply doesn’t keep time well and in the beginning many left the factor with issues running at 20+ per day.

Their newly released mechanical movements have sadly proven disappointing.

I truly get the feeling that GS has been rushing their new movement intros (including the 9SA5 in the Birch models) without first resolving their teething issues.
I tried the chronograph function on all of the brand-new Tentagraphs in stock at one AD and, sure enough, they all skipped.

I know of some Birches that needed a spa treatment to ensure accuracy. In GSs Defence this was done without fuss, free of charge and fast.

but I've given it a pass, since I usually rotate watches often anyway.

"When everyone experiences the same software bug it becomes a feature."

I'm going to recycle that when explaining my personal bugs to the mrs.

I read that it would need to go back to Japan for any servicing. I don't think the Tentagraph is an integrated chrono.

In fairness to GS, I perhaps add that I've not had any issues with any of their earlier calibers (whether automatic, hand-wound, or Spring Drive).

I have had several rare GS models go back and it's not been a problem...

but several of the ADs (excluding the one where I got my Tenta, who was non-committal) whom I initially consulted said the modular aspect should not be a factor in perturbing the running-seconds hand.

It would most likely not have ended up under the tree (unless Santa was to include a heftier left wrist in addition) but good to know. Don’t remember this from the 8R48 movement…

I can vouch for the proper functioning of the 8R46 movement in my Speedtimer line as well.

I also noticed another issue linked to the chronograph function on an older blue dial Tentagraph at a local AD. Not sure if GS has addressed it in later releases.