Post by CTGull on Dec 27, 2023 14:40:05 GMT -5
Japan Date Codes
While the serial number is may or may not be visible, and the 6 & 7 digit serial numbers are not usable to determine the date of manufacture, there is a Date Code ink stamped on the inside of nearly all early FG’s, except most FG-75’s, and a few oddballs they forgot to stamp. This date code will be very close to when the guitar was built. Typically 3 to 6 weeks before it’s finished.
• The date code is located one of the sides of the lower bout. Sometimes both or on the end block.
• The format is YY.MM.DD.
• The year isn’t the normal year we are used to. It’s the Japanese year based on the reign of the current Emperor. In this case, it’s the SHOWA period, the reign of Emperor Hirohito, which started in 1926. Year 1 is 1926, therefore year 41 is 1966. 41.6.18 would be June 18, 1966. More info here - Japanese Emperor Date Codes
• This date code was probably stamped when they made the sides, not when the guitar was assembled. I’ve seen a few guitars where the date code is partially under the kerfing.
• Some guitars did not get a serial number or it has faded over the years, so the only way to know about when the guitar was made is by this date code.
• It seems not many people in the US know about the date codes, although they must be better known in Japan.
• The date code isn’t always visible thru the sound hole.
• The best way to find it is to put a flashlight inside the guitar and use the camera on your cell phone (zoomed in slightly) to look around inside. Another option is a USB endoscope that is plugged into your cell phone. The visual quality isn’t as good as the cell phone camera, but the length and flexibility allows you to get closer.
• The date codes are in most vintage Yamaha guitars, except for most FG-75/FG-75-1’s, some rosewood models (the wood is too dark to read it), and a few they forgot. I have examined many FG-75’s and have only found (2) with date codes, there were no visible internal markings other than the serial number.
• There is typically a single larger number ink stamped on each of the sides. I had assumed those are detail numbers so they use the right side pieces for that model guitar, but I’ve found many inconsistencies, it’s probable they are inspection marks.
• The Date Code is typically next to one of these large numbers.
Japan Internal Date Code
Once I discovered the internal date codes I knew I could compare known 6 & 7 digit serial number/date code sets with other serial numbers and make a good guess as to when other guitars were made. Currently I am up to 3000 serial numbers and 470 date codes. I got started by searching, asking for serial numbers & date codes, and putting them in a spreadsheet. I’ve also recorded the link of where I found the data, just in case I had to go back. Which I have many times as I’ve found more subtle variations.
Finding serial numbers isn’t too hard. Search & ask. But the date codes are needed as reference points. Those are hard to find. I found a Japanese guy on YouTube who made videos of himself playing many early FG’s, and he mentioned the serial number and date code most of the time. He also has a website (in Japanese) dedicated to the FG-150. A few curious people I’ve asked have found date codes inside their guitars, but I can’t expect most people to go that far. When I find vintage FG’s locally on CraigsList I will ask if I can see the guitar and take pictures. But they’re very rare.
After I started recording serial numbers, and other data, I realized I could figure out when the various labels changed.
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While the serial number is may or may not be visible, and the 6 & 7 digit serial numbers are not usable to determine the date of manufacture, there is a Date Code ink stamped on the inside of nearly all early FG’s, except most FG-75’s, and a few oddballs they forgot to stamp. This date code will be very close to when the guitar was built. Typically 3 to 6 weeks before it’s finished.
• The date code is located one of the sides of the lower bout. Sometimes both or on the end block.
• The format is YY.MM.DD.
• The year isn’t the normal year we are used to. It’s the Japanese year based on the reign of the current Emperor. In this case, it’s the SHOWA period, the reign of Emperor Hirohito, which started in 1926. Year 1 is 1926, therefore year 41 is 1966. 41.6.18 would be June 18, 1966. More info here - Japanese Emperor Date Codes
• This date code was probably stamped when they made the sides, not when the guitar was assembled. I’ve seen a few guitars where the date code is partially under the kerfing.
• Some guitars did not get a serial number or it has faded over the years, so the only way to know about when the guitar was made is by this date code.
• It seems not many people in the US know about the date codes, although they must be better known in Japan.
• The date code isn’t always visible thru the sound hole.
• The best way to find it is to put a flashlight inside the guitar and use the camera on your cell phone (zoomed in slightly) to look around inside. Another option is a USB endoscope that is plugged into your cell phone. The visual quality isn’t as good as the cell phone camera, but the length and flexibility allows you to get closer.
• The date codes are in most vintage Yamaha guitars, except for most FG-75/FG-75-1’s, some rosewood models (the wood is too dark to read it), and a few they forgot. I have examined many FG-75’s and have only found (2) with date codes, there were no visible internal markings other than the serial number.
• There is typically a single larger number ink stamped on each of the sides. I had assumed those are detail numbers so they use the right side pieces for that model guitar, but I’ve found many inconsistencies, it’s probable they are inspection marks.
• The Date Code is typically next to one of these large numbers.
Japan Internal Date Code
Once I discovered the internal date codes I knew I could compare known 6 & 7 digit serial number/date code sets with other serial numbers and make a good guess as to when other guitars were made. Currently I am up to 3000 serial numbers and 470 date codes. I got started by searching, asking for serial numbers & date codes, and putting them in a spreadsheet. I’ve also recorded the link of where I found the data, just in case I had to go back. Which I have many times as I’ve found more subtle variations.
Finding serial numbers isn’t too hard. Search & ask. But the date codes are needed as reference points. Those are hard to find. I found a Japanese guy on YouTube who made videos of himself playing many early FG’s, and he mentioned the serial number and date code most of the time. He also has a website (in Japanese) dedicated to the FG-150. A few curious people I’ve asked have found date codes inside their guitars, but I can’t expect most people to go that far. When I find vintage FG’s locally on CraigsList I will ask if I can see the guitar and take pictures. But they’re very rare.
After I started recording serial numbers, and other data, I realized I could figure out when the various labels changed.
Back to the TABLE OF CONTENTS