Rasierklingenfeld-Reißer

Immer wenn der Rasierklingenfeld-Reißer oder die ausgerüstete Kreatur angreift, erhältst du {E} (eine Energiemarke), dann erhält er bzw. sie bis zum Ende des Zuges +X/+X, wobei X gleich der Anzahl an {E} ist, die du hast.
Rekonfigurieren — Bezahle {2} oder {E}{E}{E}. (Bezahle {2} oder {E}{E}{E}: Lege diese Karte an eine Kreatur deiner Wahl, die du kontrollierst, an oder löse sie von einer Kreatur. Spiele Rekonfigurieren wie eine Hexerei. Solange diese Karte angelegt ist, ist sie keine Kreatur.)

Éventreur des Champs de Rasoirs

À chaque fois que l'Éventreur des Champs de Rasoirs ou la créature équipée attaque, vous gagnez {E} (un marqueur « énergie »), puis l'Éventreur des Champs de Rasoirs ou la créature équipée gagne +X/+X jusqu'à la fin du tour, X étant la quantité de {E} que vous avez.
Reconfiguration — Payez {2} ou {E}{E}{E}. (Payez {2} ou {E}{E}{E} : Attachez à une créature ciblée que vous contrôlez ; ou détachez d'une créature. N'utilisez la reconfiguration que lorsque vous pourriez lancer un rituel. Tant que ce permanent est attaché, ce n'est pas une créature.)

剃刀ヶ原の切り裂き獣

剃刀ヶ原の切り裂き獣や装備しているクリーチャーが攻撃するたび、{E} （エネルギー・カウンター１個）を得る。その後、ターン終了時まで、それは＋Ｘ/＋Ｘの修整を受ける。Ｘは、あなたが持つ{E}の個数に等しい。
換装―{2}か{E}{E}{E}を支払う。（{2}か{E}{E}{E}を支払う: これを、あなたがコントロールしているクリーチャー１体を対象としてつけるか、クリーチャーからはずす。換装はソーサリーとしてのみ行う。ついている間、これはクリーチャーではない。）

Razorfield Ripper

Whenever this creature or equipped creature attacks, you get {E} (an energy counter), then it gets +X/+X until end of turn, where X is the amount of {E} you have.
Reconfigure—Pay {2} or {E}{E}{E}. (Pay {2} or {E}{E}{E}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Modern Horizons 3 Commander

Whenever Razorfield Ripper or equipped creature attacks, you get {E}, then it gets +X/+X until end of turn, where X is the amount of {E} you have.
Reconfigure—
Pay {2} or {E}{E}{E}.

Whenever Razorfield Ripper or equipped creature attacks, you get {E} (an energy counter), then it gets +X/+X until end of turn, where X is the amount of {E} you have.
Reconfigure—
Pay {2} or {E}{E}{E}. (Pay {2} or {E}{E}{E}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Although it causes an Equipment to become attached to a creature, reconfigure is not an "equip ability" for the purpose of cards like Fighter Class and Leonin Shikari.

An Equipment creature can never become attached to itself. If an effect tries to do this, nothing happens.

An Equipment creature with reconfigure can be attached to creatures by effects other than its reconfigure ability, such as the activated ability of Brass Squire.

An Equipment doesn't become tapped when the permanent it's attached to becomes tapped. For example, if you attack with a creature that is equipped with Razorfield Ripper, then use reconfigure to unattach Razorfield Ripper after combat, Razorfield Ripper will be untapped and could be used to block during your opponent's turn.

As soon as an Equipment creature with reconfigure stops being a creature, any Equipment and Auras with enchant creature abilities become unattached. Auras that can enchant an Equipment that isn't a creature remain attached to it.

Attaching an Equipment with reconfigure to a creature causes that Equipment to stop being a creature until it becomes unattached. It also loses any creature subtypes it had.

Energy counters are a kind of counter that a player may have. They're not associated with any specific permanents.

Energy counters aren't mana. They don't go away as steps, phases, and turns end, and effects that add mana "of any type" can't give you energy counters.

If a permanent with reconfigure is somehow still a creature after it becomes attached (perhaps due to an effect like that of March of the Machines), it immediately becomes unattached from the equipped creature.

If a spell or ability with one or more targets states that you "may pay" some amount of {E}, and each permanent that it targets has become an illegal target, the spell or ability won't resolve. You can't pay any {E} even if you want to.

If an Equipment with reconfigure somehow loses its abilities while it is attached, the effect causing it to not be a creature continues to apply until it becomes unattached.

If an effect says you get one or more {E}, you get that many energy counters. To pay one or more {E}, you lose that many energy counters. You can't pay more energy counters than you have. Any effects that interact with counters a player gets, has, or loses can interact with energy counters.

Keep track of how many energy counters each player has. Potential ways to track this include writing theme down on paper or using dice, but any method that is clear and mutually agreeable is fine. (At higher levels of tournament play, dice may not be allowed for tracking counters that players have.)

Reconfigure represents two activated abilities. Reconfigure [cost] means "[Cost]: Attach this permanent to another target creature you control. Activate only as a sorcery," and "[Cost]: Unattach this permanent. Activate only if this permanent is attached to a creature and only as a sorcery."

Similarly, if an Equipment is tapped, its reconfigure abilities may still be activated and it may still become attached to creatures. Becoming attached doesn't untap it. In most cases, an attached Equipment being tapped won't affect gameplay, but it will be relevant if it becomes unattached again before it untaps.

Some spells and abilities that give you {E} may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't get any {E}.

Some triggered abilities state that you "may pay" a certain amount of {E}. You can't pay that amount multiple times to multiply the effect. You simply choose whether or not to pay that amount of {E} as the ability resolves.

Some triggered abilities that state that you "may pay" a certain amount of {E} describe an effect that happens "If you do." In that case, no player may take actions to try to stop the ability's effect after you make your choice. If the payment is followed by the phrase "When you do," then you'll choose any targets for that reflexive triggered ability and put it on the stack before players can take actions.

The value of X is calculated only once, as Razorfield Ripper's triggered ability resolves.

{E} is the energy symbol. It represents one energy counter.