Concentrate

Three cards for double-blue at sorcery speed, no conditions: this is the rate that draw spells got benchmarked against for years. The lineage runs deep. Inspiration tried the same effect at instant speed and shaved a card off the top to pay for the timing. Divination settled at two cards for three, the conservative successor printers reached for once the card-advantage treadmill sped up. The whole class of "draw three for four" effects (later joined by Tidings, Opportunity, and the modal kicker variants) sits on the line this card drew: pay the double-blue tax, do nothing to the board, and net two cards of advantage. What balances it is the part that never appears in the text: being a sorcery, it offers no bluff and no instant-speed response to a wrath, and it leaves the board exactly where it found it. That tempo cost is precisely why blue control decks treasured it and blue tempo decks never wanted it: spending a full turn on pure refueling only pays off when you have the time to spare. The effect has been reprinted and re-statted often enough that its specific numbers feel almost arbitrary now, but the reason it endures as a reference point is structural: four mana for raw, unconditional volume, taxed only by the tempo you forgo to cast it.