so lately I have been wanting to improve my mid-game by forcing myself to invade and fight a lot
I do this by letting my opponent occupy the 4 corners first, then I will start fights

in one game I came up with this formation

[sgf-full]http://www.lifein19x19.com/forum/download/file.php?id=1122[/sgf-full]


It seems that I let my opponent get the 4 corners, so I should be at a disadvantage.
But strangely, in the games that I used this opening, I never felt that I was behind.
Then I looked closely at this centre thing, it is

1)almost impossible to be under attack
2)has good influence in all directions
3)easy to support my other weak groups if any
4)extremely thick
(the centre doesn't have to be this exact shape, it is just a general idea)

but again, I am only 7k and my opponents are the same, so I didn't know for sure if this is a reasonable opening
For all the dan players out there, do you think this opening is playable or is it very disadvantageous?
Thanks a lot.

Openings like this are usually very fun to play, but not optimal in terms of winning games. Your formation here is pretty overconcentrated. Try to think bigger when doing stuff like this! Here's an example of Alexander Dinerchtein 3p playing something similar.

[sgf-full]http://www.gosensations.com/images/events/g1073.sgf[/sgf-full]
[sgf-full]http://www.gosensations.com/images/events/g1075.sgf[/sgf-full]

your actual formation looks overconcentrated, but it can be still used for as an exercise. there are several other patterns that you might be interested in...

- Great Wall fuseki (with a long discussion how good it is (or not))

- i think i've seen somewhere this "Great Cross", but can't find it at senseis now

- and less innovative but possibly more useful are these two sanrenseis (i often play them myself)

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