You might have sometime been told that you should make noise and ‘slurp’ your Japanese noodles
and that it is to show how much you appreciate the dish
(cf. The Right Way to Eat Cold Soba Noodles - Stop Eating it Wrong, Episode 51 - YouTube).
In my opinion, however, that is incorrect.
Oh, yes. You SHOULD make noise and slurp,
but it is not because you show your appreciation that way.
Following is what I, who am a native Japanese, have found from my experience and introspection.
As many advisers put it, one big reason is that it enhances flavour.
Slurping up noodles means breathing up into your nose the air
full of odour molecules of rich ramen aroma or of subtle scent of soba.
I do agree with them on this point, but do not think this is the biggest.
The secret of slurping is the sense of swiftness.
This may be what few have pointed out.
According to typical account of Japanology,
Japanese people do not like to stick to things too much.
Noodles have been FAST food
--if my memory serves me correctly--
since Edo period, and hence should be eaten fast.
Be quick. Do not chew them long. Just slurp up and swallow.
The slurping style certainly helps you eat fast, and on top of that,
the noise made along will make you feel it even faster.
What are noodles? Why should food be in such a string-thin shape?
I fancy that they originated from the shape of flowing water.
Like running river or falling rain,
Asian chopstick-eaten noodles ‘stream’ into your mouth, in Japan especially.
Remember that it consists of rainy islands packed with hills and mountains,
where rivers are many, short, and rapid.
It is therefore overflowed with noise of running water.
The noodle sound remindes them of cool water stream
especially in hot, humid summertime.
This is the true reason why Japanese people are so big fans of slurping noodles
and so recommended to you too.
When giving a nice slurp to your noodles, you are like a cool little stream in June Japan.
Never be a big Niagara Falls.
Or all your base are belong to us.