I'm about half-way through the first part (60 Maeda problems) of the ins and outs of life and death. The book is quite difficult and has excellent answer diagrams so I can only recommend it for serious dan students above 2d kgs (perhaps 3-4d is more suitable). I've also done the first part of GGPfD vol 7 which is the opening and middle game problem book. The first part about the opening was a piece of cake, but the middle game problems are a different thing entirely. I got almost all of the ones I solved wrong. Answers are educational so it's good work.
I'm at game 10 of invincible, though it has to be said that I skipped the first two games because I've already done them a couple of times. I think I might want to repeat this book after I've done all the games, just like with tsumego books repetition seems to be good.
On the subject of replaying pro-games (especially with commentary): I've found that alot of players around my level play improper, unelegant moves all the time, both on IGS, Tygem and KGS. These improper moves are often responded to improperly by me, starting huge violent fights or something else that leads to an odd game with 'unprofessional' shapes all round. What I'm trying to say is that you can't really learn that much from just imitating the players you play against. Playing a ton of games against such players will probably lead to bad habits through imitation. This imitation is a consequence of only seeing the same type of moves over and over again. For example, alot of players on tygem like to play the handicap attachment from the 4-4 point. I've set up an arbitrary position below.
$$c Example of 4-4 attach 'tygem joseki'
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O . . X . . X . . . . . . a b . . |
$$ | . . . O . . . . . 8 . . . 7 . X 5 . . |
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . O . . . . . . . . . . . 3 1 W . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | X O X O . . . . . . . . . . . . . . . |
$$ | . X O , . . O . . O . . . . . X . . . |
$$ | . O . O . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c Example of 4-4 attach 'tygem joseki'
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O . . X . . X . . . . . . a b . . |
$$ | . . . O . . . . . 8 . . . 7 . X 5 . . |
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . O . . . . . . . . . . . 3 1 W . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | X O X O . . . . . . . . . . . . . . . |
$$ | . X O , . . O . . O . . . . . X . . . |
$$ | . O . O . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
This is one of those 'tygem' joseki moves and I theorize it has come about from the players on tygem imitating players that are a bit stronger than them, stealing their tactics to win but never actually realizing the proper play is a pincer of backing off. In the diagram I have artifically constructed, the position is meant to illustrate some weaknesses of the attachment. First white 8 is the shoulder hit reduction. If you don't like black's result it's possible for white to try the guerilla tactic of playing at a. Alternatively, if a black wall is really good on the top but not very nice along the right side, white can invade at b, taking the corner profit. On Tygem, there's also a preference for establishing large territorial frameworks all the while invading your attempts at the same thing like mad. Sometimes punishing such invasions requires indirect finesse, a touch of elegance or some strategic principle other than brute force. It's through studying the subtle depth of professional games that you can learn to appreciate such things, aswell as proper shape, fighting spirit and flow of stones.
There's also a certain kind of thinking that can only be grasped from studying high level games. For example, a first line kosumi move to capture stones instead of bending. I hope you know what I mean. The kosumi is played to give the option of a ko later. This difference in thinking also encompasses principles like 'attack is the best form of defense' and knowing when you must protect your shape or get harassed. Also when you should sacrifice a group because running it away would lead to a huge loss. Setting up exchanges to gain benefits elsewhere is flexible and this flexible mindset is very important for me to remember sometimes. I can be a bit stubborn. Instead of doggedly pursuing an unclear and probably bad course of action, stop and think at each move if there's a better way. Maybe you made a wrong move, but you don't have to continue your descent into ruin. Maybe there's a way to recover, to set up some kind of exchange or use your dead group for ko threats elsewhere. One must be flexible, bending without breaking. Looking at the board as a whole. Knowing when to tenuki and when to protect your shape with a seemingly slow move (example: yoda norimoto game in a previous post).
So in short, as a student of the game without a teacher, one must acquire both tactical and strategical strength, but how? Theory Books+pro games provide one side of this while problems provide the other. They are both important, but your strategy can only come to fruition if you have the tactical strength to back up your plays and counter your opponents plays.
I'm thinking about joining the YGD sometime in the future. I think having a strong teacher to point out mistakes in my games is very valuable. Also, those games are more serious than most internet games. There's also alot of lectures to make it easier to study the strategical principles of go. Something which can be very hard for self-taught people like myself to come by. However, I feel like improving my reading is still extremely important. That being said, having studied some of Shusaku's games in invincible, I am beginning to realize the value of sound strategic principles and the professional way of thinking. So I will continue to improve both!