Position of the watch affects accuracy.

I’ve heard similar but don’t have an answer for you. It might depend on the movement?

It geeatly depends on the architecture of the movement!

Generally, it is the truth, but each movement is different.

Gravity is real so your statement is true, not a myth.

That works for pretty much all of my Miyota movements, but less so for my Swiss-made ones.

It’s been true with my watches that have ETA’s in them. For example, my Hamilton Khaki Field automatic runs about -3 a day while I use it throughout the day. At night I keep it crown down and it speeds up enough to get 2 seconds back just losing a second the next day in total.

My Longines Spirit Zulu Time which has a chronometer movement in it gains about 2 seconds throughout the day. That watch gets put down with the crown up and it slows it down enough to come in at about +1 with at times coming in at +/- 0 seconds. I went on a trip to Europe with it last month for about 10 days. I set it to 0 the day before we left and when we came back home, it had gained a total of 6 seconds. She’s definitely a keeper.

My watches with ETA movements are rock solid time keepers.

I have a Seiko with an NH34 movement and most times it does whatever it feels like doing that day regardless of position when it’s stored.

It’s not that linear. Depends on the type of movement, components and even the position of the balance wheel within the movement.

With the Seiko Alpinist SPB155J1 and 6R35 movement this is true. Faster with the dial up and slower on the crown or worn. Wearing it every day it achieves a certain precision over a long period. My other watches with Swiss movements, however, are much less affected by position.

Simple solution is for you to get a tourbillion watch. 😁

I'm currently in the process of self regulating my Seiko Sarb035, and have been using a "Watch Accuracy" app on Android as a timegrapher. I have also noticed that the watch runs significantly faster dial up and dial down, moreso dial down.

You can verify with a Timegrapher app.

What is in the photo?

My 4R works that way: +2s on wear and -6s over night crown up

My Sellita SW200-1 has no positional variance

Gyroscopic tourbillion owners must be feeling very vindicated rn lol

Riveting a new balance staff.

While I know the Timing is different in the position, I don’t know if it is always in the manner you mentioned. I tend to put the watch overnight in a crown up or down position to even things out.