This is your standard run-of-the-mill blue counter/flash deck with some out of place counter spells.

How It Plays

Like a true blue mage this deck only plays on the opponents turn. There is not a single card in here that cannot be played at instant speed. The goal is to counter the important cards of the opponent and yourself keeping one to two threads continuously picking at him.

The first few turns you mostly will only end up with a Spectral Sailor, if you have it turn one. Otherwise it is countering all the opponent's stuff that has even remote potential to get dangerous. The deck runs a total of 15 counter spells helping to suppress hopefully about everything that an opponent tries to do. At some point get a flying Sea-Dasher Octopus for the card advantage. Slowly you'll want to deploy a few creatures on the board and from then on protect them and counter about everything that the opponent does.

Why not Dimir?

I tried Dimir Flash with Blacklance Paragon and Slitherwisp. It turned out you really want to have untapped lands in blue decks. Anything that potentially enters tapped is bad in the first few turns. You need to be able to disrupt the opponents build-up! And I don't have the untapped lands and won't craft them. Also didn't get a Dirge Bat, which would still have been a good inscentive to follow the Dimir path. Pure blue just seems to run way more consistent.

Details

In this deck your basic own turn is very simple: Play a land and attack with creatures. Everything else should happen on the opponent's turn.

Our creatures consist of the pre-Ikorian Spectral Sailor - a cheap flyer that can draw card when there is nothing else to do with the mana. Brineborn Cutthroat as one of main attackers that will grow everytime we play a spell on the opponent's turn; and that should be the case for about any spell. And Brazen Borrower as the bouncy 3/1 flyer.

With Ikoria we have some interesting additions to the decks creature base: Cunning Nightbonder makes all our other creatures cheaper by one mana and makes them un-counterable. Sea-Dasher Octopus is the new Curious Obession and most of the time goes on one of the flyers - with the Nightbonder for the same mana cost, but at instant speed. It potentially draws you an extra card each turn. Need to get to your counter spells! And the third Ikoria card is Voracious Greatshark, a - sort of - Frilled Mystic that counters less stuff (only creatures and artifacts), but has a bigger body.

Now, the annoying part of this deck are the Instants and Enchantments. In total we have 15 counter spells - including the shark. Aside of the Omen of the Sea everything is a counter spell.

We have an assortment of counters for creatures and noncreatures, as well as generic counters. The cheap, specific counters like Essence Capture, Negate, and Quench are especially good in the early game. With a good number of decks containing blue running around this also is true for Mystical Dispute.

The generic counter spells are the usual "good" ones: Sinister Sabotage, Ashiok's Erasure, Tale's End, and Mystical Dispute. The Erasure and End are the random ones in the pile, but are doing their job well. A nice thing about Ashiok's Erasure is that it can really shut down key cards of the opponent by prohibiting other copies of them also to be played. And Cunning Nightbonder makes it one mana cheaper, so brings it down to default counter spell costs. With the new companion mechanic and all companions being legendary creatures Tale's End gets a boost in playability as the companions are often key cards in the opponent's deck.