(stolen from http://tappedout.net/mtg-decks/how-to-kick-ass-with-codex-shredder-101/)
"It's time to Codex Shredder and chew bubblegum, and I'm all out of gum."-GoldGhost012, The Man Who Trained James Bond
Basically the most annoying mono-blue deck that doesn't run Devotion. No AEtherling either, because it's just cliche.
No, this wincon has to be more sophisticated. More grindy. More fun. And that wincon is Codex Shredder . With a healthy dose of Traumatize , because milling is fun.
Did you know Codex Shredder forms a nice synergy with Griptide ? Remove their best creature, then mill it with the Shredder. Now they don't get to draw it next turn!
The sideboard is meant to counter mostly aggro and other aggressive decks. Here, let me break it down for you:
AEtherize : A mini Cyclonic Rift . Very good against decks that attack with many creatures and tokens. Recast everything!
Ratchet Bomb : This deck's only answer to Mistcutter Hydra . That's not the only thing it can hit though; it destroys tokens with no effort and destroys aggro's low-costing board pretty easily.
Jace, Memory Adept : You might be wondering "WHY THE HELL ISN'T THIS MAINBOARDED?!?!" and calling me crazy for not doing it. Thank you for the compliment, but isn't the shock factor enough of a reason? They go an extremely long time for the first game, then the second game they think all you have is Codex Shredder and Traumatize , and then you plop Jace. Plus Hero's Downfall and Dreadbore are things.
Stymied Hopes : The counter's counter. Effective early game against aggro, somewhat effective late game against control. They tap out to cast or counter and you shout "Surprise!" and scry while they take a while to respond to the fact that they just got countered by a counter that's not that great outside Limited.
Pithing Needle : Stops Pack Rat , AEtherling , Gods, and Planeswalkers. I don't think I need to explain anything else. Does your head hurt yet?
Let me break down how I would sideboard in against specific and popular match-ups.
Aggro:
Probably this deck's biggest problem. I'd add 3x AEtherize , 4x Stymied Hopes , and 3x Ratchet Bomb , removing 3x Griptide , 4x Cancel , and 3x Mindstatic .
Esper Control:
Ha, I laugh at their removal. Bring in 3x Jace, Memory Adept , 4x Stymied Hopes , and 2x Pithing Needle . Note, Jace probably shouldn't be cast until you have enough mana to cast him and play a counter-spell for Hero's Downfall .
Mono-Blue Devotion:
Only Jace, Memory Adept needs to come in. Mindstatic can come out. Although really anything not named Stymied Hopes can come in if you feel you need it. Remember that triggers go on the stack before they resolve, so you can totally Voyage's End their Nightveil Specter before the Master of Waves trigger resolves.
Mono-Black Devotion:
2x Pithing Needle , 3x Ratchet Bomb , and 3x Jace, Memory Adept come in. 3x Griptide , 2x Voyage's End , and 3x Mindstatic come out, although Voyage's End and Mindstatic are switchable. Again, try not to play Jace unless you have a counter-spell in hand.
Azorius Control:
Just let them draw with Sphinx's Revelation , it'll help your wincon. 2x Pithing Needle , 3x Jace, Memory Adept , and 4x Stymied Hopes can come in. Board out 3x Mindstatic , 3x Voyage's End , and 3x Griptide . Always have a counter or Cyclonic Rift in hand for Detention Sphere when Jace hits the field.
In any of these matches, if you ever feel that Traumatize under performs, board it out.