Strategy: Lock down opponents early with Hands of Binding and Rathi Trapper, free up mana for counters and trapping with Hidden Strings, and close out the game with Helm of Ghastlord or Shadow Slice on an unblockable (and possibly hexproof) creature. Elgaud Shieldmate is the hidden gem of this deck, helping prevent 2-for-1 card loss. Weak points are dealing with resolved artifacts and enchantments, hence a relatively high number of counters both in the main and sideboard. Card draw with Betrayal and the Helm is important as some 2-for-1 loss is expected.
Note that to really lock down an opponent requires a combination of Trapper/Hands of Binding and the tap/untap of Hidden Strings. There are times where you will want to untap your opponents creatures with Hidden Strings in order to tap them again immediately with Hands of Binding (on the same attack, as you can choose the order of how the effects are resolved as far as I understand). Preventing your opponents from attacking is what you want, so you use Rathi Trapper on your opponents turn to stop their attack, not on your turn to prevent them from blocking (your attackers are unblockable anyway).
If you are playing a blue deck that has counter spells, you can use Hidden Strings to tap your opponents land so they can't play counters - then use your mana to play an aura like
Helm of the Ghastlord
(a key spell that you don't want countered).
The sideboard is used to tweak the removal and counters. Only a hexproof opponent requires a change of strategy by the full removal of Hands of Binding and Rathi Trapper.
A primer on how to use Hidden Strings:
This is a rough rank order of what to use Hidden Strings for: 1) tap opponent's land to stop their counter spells, 2) tap your opponents creature IF you have
Betrayal
on it to draw a card, 3) untap your land to play more cards (this will probably be the most common use of Strings), 4) untap opponent's creature to then freeze them with Hands of Binding or the Trapper, 5) untap your creatures for a vigilance-type effect.
This order can change in importance depending on the situation, eg. the fifth one is the most important if you need more defenders to stop a lethal attack.
Ideal T1-T6:
T1: Land, play Triton Shorestalker.
T2 (blue only): Land, play Hidden Strings before they can counter it (only if they're land is tapped).
T2: Land, play Hands of Binding, attack with Triton Shorestalker (freezing one or two creatures). Hidden Strings is good against mono-blue here to stop a counter but is not ideal at this point in the game if you are going against an aggro attack deck - but you can use it to untap both lands on this turn and play another creature if you have no Hands of Binding, or you can use it to tap your opponents land so they can't play a counter. Playing too many Shorestalkers early backfire if your opponent has Echoing Decay or good/bounce removal spells. (It is always better to play a Dimir Infiltrator as your second creature, rather than a second Shorestalker, because of the 3 toughness.)
T3: Land, play Dimir Infiltrator, play Disfigure to remove a threat, attack with Shorestalker and freeze any new creature on board.
T4: Land if you have one, then play Hidden Strings on Dimir Infiltrator (untap opponents frozen creature so you can freeze it again, and/or untap a land), attack with Shorestalker and Infiltrator (freeze creature if possible, otherwise just untap your lands), with four untapped lands, you now have option to play a 2- or 3-mana creature and leave 1 or 2m open for a counter or Disfigure. If you dont have Hidden Strings in your hand by this turn, play Rathi Trapper instead.
T5: You can start missing land drops, doesnt matter much if you have 4 down thats enough to drive your game (only one spell needs 5 mana and it's your closer for end of game). The tempo will shift your way on this turn if you can play a Helm and attack, or play a Shieldmate and attack again with a hexproof creature. You should have Hidden Strings down by now to untap land for a counter on your opponents next turn. Once you have a Rathi Trapper in play, Hidden Strings is used mainly to untap your lands so you can use them twice in one turn).
T6-8: Now use your counter spells whenever you can to keep your opponent from getting back on track. If you dont have a Helm down yet, its going to be a long game because you are only doing roughly 1-4 points of damage per turn. Helm and
Shadow Slice
are your only ways to do heavy damage - protect them by tapping your opponents land so your spells can't be countered.
Sideboard strategy (revised 18-Oct):
Affinity: -4 Disfigure, -1 Mana Leak, +3 Counterspell, +3 Stab Wound (for Spire Golem). I'm not sure how to deal with a resolved Atog - maybe leave Disfigure in if you see Atog and not Spire Golem. Definitely try to counter Atog.
AzoriusKitty: -4 Disfigure, +2 Counterspell, +2 Stab Wound (for Skyfisher or Dreamstalker, then hope you can counterspell when they try to lift it back into their hand).
BorosKitty: -2 Disfigure, -2 Nightshade Stinger, +2 Counterspell, +2 Stab Wound (fits perfectly on a Skyfisher).
Burn: -2 Hands of Binding, -3 Disfigure, +2 Dispel, +3 Counterspell (plus -1 Disfigure for +1 Stab Wound if they play any creature with 3+ toughness).
Delver: -2 Hands of Binding, -2 Nightshade Stinger, -1 Helm of Ghastlord, +2 Dispel, +3 Counterspell. If that turns out to be more counters than you needed, for game 3: -1 Counterspell, +1 Helm of Ghastlord.
DelverFiend: -4 Disfigure, +2 Counterspell, +2 Stab Wound (for Nivix or Dragonauts).
Dimir Mill: -4 Disfigure, -2 Hands of Binding, +3 Counterspell, +2 Dispel, +1 Stab Wound (assuming they have Defenders).
Dimir Control/Teachings: -2 Hands of Binding, -2 Disfigure, +2 Dispel, +2 Counterspell. Also -2 Disfigure for +2 Stab Wound if they are using 3+ toughness creatures (defenders).
Elves: -2 Hidden Strings, -2 Nightshade Stinger, -2 Mana Leak, +3 Echoing Decay, +3 Counterspell.
Familiars: -2 Hands of Binding, +2 Counterspell. I dont know what else to do here.
Goblins: -2 Nightshade Stinger, -3 Hidden Strings, -1 Helm of Ghastlord, +3 Echoing Decay, +1 Chainer's Edict, +2 Counterspell.
Hexproof: -2 Hands of Binding, -4 Disfigure, -1 Rathi Trapper, -2 Betrayal, +4 Chainers Edict, +3 Counterspell, +2 Dispel. If they are using Aura Gnarlid or some non-hexproof creatures, you can add +3 Stab Wound instead of Dispel and another Trapper. Keep Hidden Strings and use it on your own creatures (vigilance) and land.
Illusory Tricks: -2 Nightshade Stinger, -4 Disfigure, -1 Mana Leak, +3 Stab Wound, +3 Counterspell, +1 Dispel.
Infect: -2 Morsel Theft, -2 Nightshade Stinger, +2 Echoing Decay, +2 Dispel (if they are using instant pumps like Giant Growth) OR +2 Counterspell (if they are using non-instant aura pumps).
Izzet Control: -2 Hands of Binding, -2 Nightshade Stinger, -1 Helm of Ghastlord, +2 Dispel, +3 Counterspell.
Love Train: -4 Disfigure, -2 Hands of Binding, +3 Counterspell, +3 Stab Wound.
MBC: -2 Hands of Binding, -3 Disfigure, +3 Counterspell, +2 Dispel.
MUC: -2 Hands of Binding, -2 Disfigure, +2 Counterspell, +2 Dispel.
Rakdos (aggro/removal): -2 Hands of Binding, +2 Dispel. If no major creature threats, then -3 Disfigure for +3 Counterspell.
Slivers: -2 Nightshade Stinger, -1 Helm of Ghastlord, -2 Hidden Strings, +2 Stab Wound (on Muscle Sliver or other lords), +3 Echoing Decay.
Stompy: -2 Nightshade Stinger, -3 Hidden Strings, -1 Helm of Ghastlord, -1 Triton Shorestalker, +4 Chainer's Edict, +3 Echoing Decay.
Tron: -4 Disfigure, +2 Counterspell +2 Stab Wound.
White Weenie: -2 Nightshade Stinger, -2 Hidden Strings, -1 Helm of Ghastlord, +3 Echoing Decay, +2 Counterspell.
