After WW2 I understand some far-thinking Japanese business men bought forests suitable for wood for pianos . Obviously the acoustic guitar wasn't REALLY popular at that time but Elvis was coming with his Martin. When time moved on, the Japanese were in a prime position to churn out guitars which looked like Elvis's.At he end of the 60's I, and many others bought Yamaha FG 180 ( being unable to afford the very highly priced (in the UK) Martin D28.
I don't wish to be libelous , but , the Japanese at that time simply copied the best which was around and the FG 180 was as good a copy of the D28 that they could afford , but they DID do a good job on it. In order to get into "the market " they put a lot of good work into them.
I know a group the Teesside Fettlers who used to travel to gigs with them on car roof racks in cheap cases , through all sorts of British weather and they never warped or misbehaved.
A few in the thread mentioned the FG 140 which was almost the same as the FG 180, but the FG 140 had plastic machine head finish whereas the FG 180 had metal.
Someone also mentioned FG 150 but this one must have been a "special" or nylon strings - as I have never seen one.
At their time they were a good ,accurate, good-sounding affordable workhorse of a guitar and mine is still still eminently playable although I have moved on in taste .