I located this Hitachi Saw. I'd been without a big saw for some years.
The model number PS-12 suggests it's a 12" saw. The specifications rate it 290mm; actually more like 11-1/2". The  nameplate doesn't have a date. I thought it was manufactured in the early 70s, but a fella I know at Hitachi says this was made from 1950 till 59.
It looked to me and a friend like this Hitachi 12" was used not too often and  for not too long. And then it sat in a shed rusting for decades.
Had to use a bolt extractor with a lot of the screws. Carbon Brushes were a surprise, looking pretty fresh. I do love that pipe handle.
WD-40 and me got the rusted blade off and I set it in vinegar. Got a sort of covered tank for that set off some from the house. It was in there a few weeks. The bolt and flanges too.
The Aluminum housing, handles and such had been painted when it was manufactures. I could see painting it was right for it as well.The old paint came off with brass wire wheels set in a drill chuck. I painted using this Aluminum colored paint for Aluminum alloys.
Separating that Steel shoe was downright easy. I knew it had been painted, but rust was so bad I couldn't tell what color. It set in vinegar for about three weeks. Finishing with removal involved some diligence with SS wire wheels and brushes set in a drill. I painted with silver rust proof.
The bottom of the shoe is left for another story.
She sounds and runs real good. But of course she needs a new blade. She's got a 1" arbor. I would have liked to use regular 5/8" arbor 10-1/4" blades. I've still got some left from the Milwaukee 6460 I had.   [//size]

Nice.

Those big saws are useful and scary both.

Thanks Bill.
Yes, useful cause I need to cut 4" in one pass. This has a depth of cut of 4-3/4. I replaced the spring that retracts the lower blade guard right off. Fact is, I check if that thing is operable before I cut.
I got a new blade for her.
This saw sure eases into things nice. When I'm ripping I have to start off before I can set the fence. She acts like a regular saw for that. Definitely is precisely right on with the shoe and blade. I could tell that right off.

Does the motor smoke or make lots of noise?  I'd think the brushes would have deteriorated after all these years

Hi there omeomai,
I'll tell ya, I've been right surprised how wrong such an expectation as that has turned out.
Right off I checked the carbon brushes like I said earlier and they sure looked like they were in the early stage of use.
And when I tested her with that old blade I couldn't believe how good things sounded. And she was cutting a 4-Inch depth all the way down better than 12 foot of length. I put her away and ordered a new blade.
I've had difficulty with getting a better fence; given the shoe's width, but mostly cause of that extra wide slot. 
Seems the fence for the current model 12 Inch saw fits just fine.
The first two picture shows how it fills that slot.
Third shows the fence is plenty long to fit across the shoe without over doing it.

Kind of surprised, by the way, that Hitachi was bringing tools to the U.S. that early; I think of the Japanese tools as hitting the U.S. market in the 1970s, but I'm obviously wrong.  Since I try to be wrong at least once a day, I've met today's quota.

Hi Bill Houghton
Actually you're right. It's just you sensed things don't seem to add up and the reason is I live in Japan. I apologize for how you understandably perceived this situation. I've lived here for many years Born in Texas though. Went to the rodeo when I was four.
I thought same as you concerning Hitachi, but very recently I've learned Hitachi tried long before the 70s.
There must have been a serious effort by Hitachi to enter the US market back in the 50s. There are extremely impressive heavy cast Aluminum tools from this decade with the Nameplate entirely in English. A good number of these high quality metal plates are struck with specifications in inches or fractions thereof. Volts 110. Yet these tools never left this country.
I've got a post coming up soon where I'll make sure to show you some of this.
Subsequently, I also looked at this 1950s big saw of mine with a new set of eyes, so to speak. Seems evident to me now the PS-12 was so named because it actually did have a 12 inch blade.Had to be a reason for that.
Referring to the picture I posted just above a little ways, when I got the new blade; that 290mm blade is the current available size. But you can see that a larger blade; a 12" (305mm) would have plenty of room to fit in there.
Right down here below is a shot from the 2020 catalog showing the current Model 12. That 290mm blade fills that out with no room to spare.
Why this early vigorous effort to establish a place in the US market did not get off the ground is open to speculation. But it apparently had no success at all, as I cannot find any record, let alone physical example of these tools in America.   

I'm getting some real use out of her with a whole lot of these recycled timbers. I already ordered a new blade. I'll post something in woodworking when I got enough to show for this. She's 2,500 rpm, safer but slow going. She's ripping real nice but it is hard work with the blade at full depth of cut, especially going uphill.