MR. Ricca stated back in 2014~ that the maker of the H.T. Winged safety was unknown and likely would never be known. To this date no Contract information has been found.
I noted MR Ricca's comments but didn't mark down where I read them.
Knowing how good Bill was at finding and documenting Contracts..... is partly why I believe there was no single recorded Contract to be found here in the US.
My thoughts lead to believing these safeties were contracted in post War Japan, as part of a bigger contract while we had them doing their version of our Rebuild program on the Carbines, Garands etc.
All this post war rebuild and build up was done under the leadership of the new *Emperor* General MacArthur holding the post as Supreme Commander for the Allied Powers (SCAP) until 1951 when he was relieved by President Truman. From 1945 - 1951 Emperor MacArthur pressured and received from the US government over 3.5 million tons of food and $2 billion dollars of emergency aid. A long list to include setting up a new Constitution, education...etc etc all done during his time of dominance.
Back to Howa:
Howa built many rifles for Japans war use. AS part of the rebuilding of Japan they were used to built parts under US supervision to our specifications. Exactly as we would expect from our other Sub/Prime suppliers.
We set up the equipment for them, Supervised and Inspected the parts... and note that the measurements were built to standard specs, Not Metric.
It was easier to do this because of the logistics involved. And there was no shortage of workers. The US used Japan for support both during the post WWII Occupation and Pre/during the Korean conflict.
Japan had many enemies from before hitting us at Pearl Harbor, the Chinese, Korea etc.
The US used Japan as a staging area for the upcoming battle with North Korea. And for any potential area to curb the rise of communism at the time.
Again: Howa making the H.T. safety is still my best Guess.
Those (If any) who might want to research this needs to concentrate just on Howa's Post WWII history during the occupation years up to about the Korean era ~1953.
Building the Thailand carbines, the sporting models for Japanesehunters and the later commercial versions for export have nothing to do with the US/Japan contract or these H.T. marked safeties.
Again FWIW,