Réduction de cout

Si un artefact indique que mes sorts coûtent 1 de moins à jouer est-ce que je peux faire un éclair de génie en piochant une carte en plus ? C’est à dire si j’ai quatre terrains est-ce que je pioche 1 ou 2 cartes ? Merci de m’indiquer l’article de la règle auquel vous vous référez.

X2B
Eclair De Génie
Ephémère
Le joueur ciblé pioche X cartes.

Tes sorts coutent 1 de moins à jouer.
donc si tu veux piocher 2 cartes ton eclair de genie te coutera bien 3U au lieu de 4U.

je ne vois pas trop où est le probleme dans ce cas.

je vois pas trop ou on peut trouver , un article de regle....voila de quoi faire la difference entre un cout à jouer, et un cout converti de mana.

K.20 - Play Cost

K.20.1 - The "play cost" for a spell or ability is what you actually have to pay to play the spell or ability. The cost may include mana and non-mana aspects. [D'Angelo 1998/02/03]
K.20.2 - The "play cost" for a spell is the "mana cost" (see Rule K.18) plus any additional cost increases or decreases that are applied. The "play cost" for an ability is the "activation cost" (see Rule G.1) plus any additional cost increases or decreases that are applied. [D'Angelo 1997/11/19]
K.20.3 - If a card's text includes "At the time you play , do ", then it is describing an additional part of the play cost. This is paid only once and is paid when announcing the card. [WotC Rules Team 1998/10/18]
K.20.4 - To figure out the total play cost: a) Start with the mana cost (see Rule K.18). b) Apply cost increases from the card itself (such as from Buyback, see Rule A.10) and cost increases from other effects (such as from Gloom). c) Apply cost reductions from the card itself (such as with the alternate cost spells, see Rule E.1) or from other cards (such as Helm of Awakening or Pearl Medallion). [WotC Rules Team 1998/02/01]
K.20.5 - Mana that is generated with a restriction on how it is spent may be spent on any play cost that meets the restriction. This means that it can be applied to increases due to Kicker, etc. For example, mana from Food Chain, which is limited to only being used for creature spells, may be used to pay the Kicker cost on a creature spell. [Rules Team 2001/05/01]
K.20.Ruling.1 - Using the Buyback (see Rule A.10) ability is part of the play cost of a spell, and is added in before you apply cost decreases. See Rule A.10.Ruling.1. [D'Angelo 1998/02/03] Kicker is also part of the play cost. See Rule A.24.Ruling.4. [D'Angelo 2001/01/16]
K.20.Ruling.2 - The result of Rule K.20.4 is that the Medallions and other cost decreasers can be applied to any part of the play cost, and not just the mana cost. [D'Angelo 1998/02/03]
K.20.Ruling.3 - Once a spell is announced (see Rule T.4), there is no way to retroactively change the play cost. It has already been paid. For example, if you use a Sleight of Mind to change Gloom so it affects green spells, it will not make an already announced green spell cost more. [bethmo 1994/11/01]
K.20.Ruling.4 - Some older cards used the text ": " on instants and sorceries. All cards using this format have errata to have it instead say "As an additional cost to play this card, pay . ." The cost is paid exactly once. Not less and not more. [D'Angelo 1999/05/01]
Note - See "Activation Cost", Rule G.1, for more information.
Note - See "Converted Mana Cost", Rule K.8, for more information.
Note - See "Mana Cost", Rule K.18, for more information.


K.18 - Mana Cost

K.18.1 - The "mana cost" of a card is the mana specified in the upper right hand corner of the card. [CompRules 2001/07/23 - 203.1]
K.18.2 - If a spell or ability specifies that the mana cost be paid, it means the actual colors and amounts specified in the mana cost. [CompRules 2001/07/23 - 203.1]
K.18.Ruling.1 - The "mana cost" does not include any additional costs in the card text, or any additional costs imposed by other cards. Those apply to the "play cost" (see Rule K.20). [CompRules 2001/07/23 - 203.4]
K.18.Ruling.2 - When a spell or ability allows you to cast a spell without paying the mana cost (or by decreasing what you have to pay), the mana cost is still considered to be the full amount even though you did not pay it. [D'Angelo 1998/02/03] See Rule K.20.
K.18.Ruling.3 - When a spell or ability allows you to cast a spell without paying the mana cost (or by decreasing what you have to pay), this will not affect costs which are not part of the mana cost. [WotC Rules Team 1998/02/01] For example, Aluren will not pay for the extra cost imposed by Gloom.
K.18.Ruling.4 - A permanent in play by an effect such as Animate Dead still has a mana cost as printed on the card, even though that cost was never paid. [D'Angelo 1998/02/03]
Note - Lands have a mana cost of zero. See Rule K.15.7.
Note - Token creatures have a mana cost of zero. See Rule K.25.5. See Rule K.25.Ruling.6 for an exception.
Note - See "Converted Mana Cost" (Rule K. for more rulings on costs.
Note - See "Play Cost" (Rule K.20) for more rulings on costs paid when casting a spell.
Note - See Rule K.28 for information on 'X' in the mana cost.

et puis voici le ruling de la carte : Heaume de l'eveil, ca peut etre plus simple à comprendre:

Helm of Awakening

Color= Artifact Type= Artifact Cost= 2 VI(U)
Text (VI+errata): Spells cost {1} less to play. [Oracle 2002/03/01]

The effect is cumulative. [Aahz 1997/01/29]
You apply the Helm to the total play cost (see Rule K.20). Since the play cost is the total of the mana cost (see Rule K.18) and all costs in the card text, this means you can apply the Helm to things like Fireball's extra targets and to Buyback (see Rule A.10) costs. The cost reduction is not applied separately to each thing, however, it is applied just once to the total cost. For example, a Capsize costs {U}{U}{1} to cast and {3} for Buyback for a total play cost of {U}{U}{4}. One Helm makes the cost {U}{U}{3} and three Helms makes the cost {U}{U}{1}. See how the reduction is applied to the total and not to individual items. [D'Angelo 1998/01/06]
The effect is applied for Kicker (see Rule A.24) the same way it is applied for Buyback (see Rule A.10). You add the Kicker to the total cost before applying any reductions. [D'Angelo 2001/07/22]
The cost reduction can apply to external penalty effects such as Gloom. [WotC Rules Team 1998/02/01] See Rule K.20.4.
The generic X cost is still considered generic even if there is a requirement that a specific color be used for it. For example, "only black mana can be spent this way". This distinction is important for effects which reduce the generic portion of a spell's cost. For example, if you had two Helms in play (each reduces the generic costs of all spells by 1), you could cast a Drain Life for just {B} and still do 1 damage. [WotC Rules Team 1997/06/01] [Duelist Magazine #19, Page 26]
Can lower the cost to zero. For example, a Brass Man. But cannot lower something below zero. [D'Angelo 1998/06/26]
The lower cost is not optional like with some other cost reducers. [D'Angelo 1997/01/27]
Can never affect the colored (non-generic) part of a play cost or any additions to the cost. [D'Angelo 1998/07/29]