Carry on JAC flight

Hi,
I a bit worried about how strict the carry on luggage policy is on the JAC turbo-prop aircrafts?

In the information it says 45 x 35 x 20 cm maximum dimensions. My backpack is a few centimeters bigger than that, so I don't know if they will throw it in the cargo and count it as another bag (+ payment for overweight...).

My current bag measures 47 x 36 x 22-24 cm...

I cannot be 100% certain, but most of the time they don't check the size of the carry-on baggage (backpacks, etc.) unless they are obviously over the size limits. I am speaking about domestic flights but on turbofan engines, not turboprop.

Every single piece of carry-on luggage is checked for domestic Japanese flights at security, using a cut out board that corresponds to the maximum allowed size at the entrance of the X ray machine. However, I have often seen security personnel lift the board and let over-sized luggage pass through. But on one or two occasions I have also seen a security personnel ask the passenger to go and check in the luggage.

However, your bag is so minutely above the upper limit, that I would be very surprised if you were asked to check it in. But I can't guarantee it.

I never flied by turboprop before, but I know they are a lot smaller. Since the backpack will be the only one I will carry (bringing a suitcase to Yakushima is a bit too much as it is quite big) with clothes and nessecities.

I wouldn't really fancy checking it in as it would contain all my valubles as well. I looked at the local bag shop but he didnt have any smaller than that either. So I guess I am in a bit of a pinch right now...

I took a JAC turboprop flight from Kagoshima to Yakushima, and the size of my carry-on wasn't checked (was just a small backpack, so it was obviously within limits). You can't know for sure if they will or won't check the dimensions, so perhaps just be prepared to pay extra if they do check and say it's over the limit.

Do you know if there is any limit size in the checked luggage?

You may check JAL website regarding that http://www.jal.co.jp/en/dom/baggage/bags/checkin.html.

Thank you.
Well seems like it would be best to put the heavy stuff in my suitcase (I will need to check in something as I carry razorblades and a small scissor...), as checking in a plastic bag or whatever would seem pretty awkward.

What's the chance of it getting lost during transit for such a small flight anyway?

And then try to crample the backpack to minimum, carrying valubles like camera, etc...

Says only maximum length 220 cm, size limit up to 50 cm x 60 cm x 120 cm, no specifics concerning check-in for specific flights. My suitcase is... perhaps, 80 cm, probably less.