The Miata MX-5 NA (1st Generation) was produced between 1989 and 1997 and sold over 400,000 units during that time.  Originally available only with a 1.6l engine, in 1993 it received a standard 1.8l engine with the 1.6l becoming optional in some markets.  The original engine was electronically fuel injected, produced 120 bhp and 100 lb-ft of torque, and was mated to a 5-speed manual transmission, with an automatic transmission as an (unpopular) option.  In US and Japanese markets, the limited-slip differential (LSD) was optional on the standard transmission.  The original NA had a top speed of 120 mph, and traveled from 0-60mph in 9.4 seconds.

The model-year 1994 (MY94) Miata MX-5 saw the introduction of the 1.8l motor capable of producing 131bhp, as well dual airbags, and LSD for some markets.  MY94 cars also received a "track bar" between the two seat-belt posts inside the car, to improve side-impact crash resistance to meet new standards.

Stats:

Production Code: NA

Available Engine(s):    1.6 L (98 cu in) B6P I4
1.8 L (110 cu in) BP I4

Transmission(s):    5-speed manual
4-speed automatic

Wheelbase 89.2 in

Length 155.4 in

Width 65.9 in

Height 48.2 in

Curb weight 2,100 lbs

Identification:

The most notable exterior feature of the NA is the pop-up headlights (which were the initiation of the "Miata Wave").  The first-generation also featured simpler body-styling, as well as smaller wheels.

I've noticed that many of the VIN number decoders currently out there give you an error if you feed them a VIN from the third-generation Miata.  To that end, here is a guide on decoding Miata VINs all the way through MY09.

Update:  You can also use our new Miata VIN Decoder to automatically decode your VIN.

Let's take a couple of example VINs from some cars for sale on AutoTrader:

We'll start with JM1NC25F680150517, here's how you break it up:

J Indicates the car's country of origin is Japan.  Could vary with other models, but Miatas are built in Japan.

M Indicates the manufacturer, M is for Mazda.

1 Indicates the type of vehicle, 1 is for cars and every Miata is a car.

NC This is the generation indicator, NA is 1st Gen (1989-97), NB is 2nd Gen (1998-2004), NC is 3rd Gen (2005-Current)

25 This is the body-style indicator for all Mazda vehicles, convertibles are 35 (1st and 2nd Gen) and 25 (3rd Gen).

F Indicates the engine-size.  1 is 1.6 liter, 3 for the 1.8l, 4 for the 1.8l Turbo, and F is for 2.0l.

6 This is a"check digit" which can be any number 0-9, or letter A-Z and it has no meaning.

8 Indicates the model year, the following is a table of all the possible values through 2009.

1990=L     1995=S     2000=Y     2005=5     2010=A
1991=M     1996=T     2001=1     2006=6
1992=N     1997=V     2002=2     2007=7
1993=P     1998=W     2003=3     2008=8
1994=R     1999=X     2004=4     2009=9

0 Indicates the manufacturing plant, almost every Miata is a 0, indicating the Hiroshima plant, but a few Miatas built between 1991 and 1993 have a '1', but Mazda says all Miatas have been built in Hiroshima.

150517 This is your production number, every new model year resets the counter to 100000, so this car is #50,517 produced in 2008.

Onto the next example: JM1NA351XP0411034

J Japan

M Mazda

1 Car

NA 1st Generation

35 Early-year convertible body style

1 A 1.6 liter engine

X Check digit, meaningless

P MY1993

0 Manufactured in Hiroshima

411034 This was the 311,034th car produced in 1993

And that is how you decode a Mazda Miata VIN Number.