RE your approach is fine, though split right at 4 or approach at a are far more common.

Your 5 is a mistake though, you lose a golden opportunity to crush black into a pathetic small shape. You noticed that black's 4 wasn't joseki (in fact his kick at 2 is bad on this board). p is the shape point to build thickness and is a good point. Your 5 would be good (though I prefer 4th line to work with your left side shape) if black had defended the p weakness with 4 at b, but as he didn't your 5 is not needed. In fact after you play p and build a massive wall of thickness your move 5 will become too close and a wasted move. Here is what could happen:

Thank you for the examples of reduction and invasion!

As a beginner, I often struggle on when to invade or when to reduce. I have lost many games due to weak groups that are not properly taken care of.... So now whenever I play, I tend to be very cautious when I may create a weak group, and be careful about cutting points. However, that would mean that I easily lose the timing of such opportunities. A big part of that is, of course, due to my inaccurate reading -- it is not easy for me to tell if (i) can my group live, and (ii) would I be living too small and giving my opponent an overly strong wall?

What could be good ways to improve on that? Thanks.

Click Here To Show Diagram Code

[go]$$W
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . . . 5 . . . |
$$ . . . . . , . 6 . 3 a X . . . |
$$ . . . . . . . . . 1 2 . . . . |
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . . . . . . . |
$$ ------------------------------[/go]

I am tempted to play at "a" to connect to W5 and fight, but then this lead to a triangle shape, which may not be good.

When approaching at 1 as white, almost everybody on WBaduk or Tygem I meet plays 2 here, but isn't black 2 a mistake without a pincer stone already in place at A or B?

Click Here To Show Diagram Code

[go]$$W
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . . . . . . . |
$$ . . . . . a . . . . . X . . . |
$$ . . . . . b . . . 1 2 . . . . |
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . . . . . . . |
$$ ------------------------------[/go]

I always thought that it was, and the sequence suggested by uberdude definitely shows one way to punish, but often black will just play a closer extension like the standard 9 handicap joseki at a, or also at b or c

Click Here To Show Diagram Code

[go]$$W
$$ . . . . . . . . . . . . c . . |
$$ . . . . . . . . . . . a b . . |
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . 3 . X . . . |
$$ . . . . . . . . . 1 2 . . . . |
$$ . . . . . . . . . . . . . . . |
$$ . . . . . . . . . . . . . . . |
$$ ------------------------------[/go]

Somehow, I can't really manage to punish this all that much. Any more thoughts on this? Or is black 2 not really a "mistake" even when there's no pincer stone?

The kick? I have never heard that term before. What is its origin? I assume you are referring to the kosumitsuke? What not just refer to it as a diagonal attachment?

The same reason we use "shoulder hit" instead of "diagonal 4th line approach to a stone on the 3rd line".

It seems to me that "kick" has entered the vocubulary in the last decade. It was not a term I ever heard when I first learned to play, but is now a term I see regularly and which I myself use when teaching beginners (or rather, I use the Dutch equivalent, of course).

But we use shoulder hit, not punch. I have always called this one a diagonal attachment. It seems more intuitive than kick, just as shoulder hit seems more intuitive than punch. I only used the term kosumitsuke to make it clear - I find Japanese terms to usually be more exact in case of possible ambiguity.

I think this is just a matter of what you are used to. I would also consider kick more specific than kosumitsuke (or diagonal attachment), as it specifically refers to a kosumi attaching downwards. This is not a kick in my book:

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . O 1 , . . . |
$$ . . . . X . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

As such, I think it is in fact as intuitive as "shoulder hit". A kick is generally a movement which is lower than your centre of gravity which touches an object (e.g. a football). That perfectly describes this move. It also fits nicely with the footsweep, one move lower, which is (in martial arts) a kick aimed at the feet of the opponent.

Interesting. I have no interest in soccer. I was raised in to watch rugby in Britain and now watch football in the USA. So to me a kick involves an upward motion and the diagram you show is more intuitively a kick than the one on the third line.

AFAIK, in rugby and American football the ball is also generally kicked from the ground? Or if it is a drop kick or punt, at least from close to the ground.

Kicks above your own centre of mass are the domain of martial arts, I would think

A kick goes from low to high - 3rd to 4th line.

Kicks above your own centre of mass are the domain of martial arts, I would think