Japanese WWII Aircraft Inspection Stamps

Hello all

First time poster, long time ‘consumer’….

I am wondering if anyone on this form knows anything about inspection stamps on components of Japanese aircraft from World War Two, as I am having trouble confirming some information I have seen in other locations on the web.

I identified sections of an A6M Zero during recent travels through the Pacific, while examining a few of the pieces I came across inspection stamps on some fragments of the aircraft. I can identify the Mitsubishi logo, what appear to be part numbers, the SDCH acronym and – the one I can’t figure – the number 17 in a small circle; there also appears to be a small Kanji character marked on the pieces that I can’t ID (see images).

[ATTACH=CONFIG]253413[/ATTACH]
[ATTACH=CONFIG]253414[/ATTACH]

The only references I’ve seen on the internet to the number in the circle is that it means ‘Showa 17’, that is, it was made in 1942 – can anyone positively confirm or deny this?

Apologies if this information has been discussed elsewhere; any assistance greatly appreciated!