I have no idea what fitting the Japanese car companies use. The old American stuff used a double flare for brake and clutch lines. The metal brake lines was made out of a soft metal. A tool will form the line into a double flare. You slide the nut on the line. Then the flaring tool is clamped onto the end of the line, and you turn a bolt that compresses the line into a mold, forming the double flare. Auto Zone will loan you the tool, if you buy the line from them and leave a deposit.
PS
The flaring tool is easy to use. It's quite simple. Just do not forget to slide the nut on before you make the flare, and always leave some extra just in case you have to cut the flare off so you can slide the nut on the next time.
