With the release of the Future Sight set and its seventy squijillion new keywords comes a new and updated Comprehensive Rules. Every set requires some bookkeeping work, and Future Sight more than most. There are many keywords for abilities new (Transfigure and Delve) and old (Lifelink and Reach); new creature types (Coward and Rigger) and a new card type (Tribal, but no Planeswalker, yet); and a number of rules that cover material formerly found only in the Glossary (see section 501, Keyword Actions).

Most of the changes are mundane, and will not affect players at all. Entries on "mana costs," for instance, have been updated to note that mana costs are sometimes printed on the left-hand side of a card. I suspect most of you have figured that out alread. But there are a few surprising changes, with real significance, and I'd like to share them with you.

First off, Two-Headed Giant is getting another tweak to the draw/play rule. We're going back to the earlier way of things: the team that plays first skips their draw step. Apparently, with the new thirty-life rule, there just wasn't any motivation to ever go second. That certainly seemed to be the case at Grand Prix: Massachusetts. I suspect that the current configuration is going to be one we'll stick with for a while.

Second, and most significant for the rules theorists out there, Characteristic-Setting Abilities have been somewhat reworked. In their new incarnation, they're known as Characteristic-Defining Abilities. This has long been a subject of confusion for players and judges, so I'll go over the parts of CDAs that haven't changed from the previous version of the rules:

• CDAs are intrinsic abilities—This is perhaps the biggest sticking point for most rules questions. A Characteristic-Defining Ability must be printed on the card it appears on (or, in the case of tokens, be granted by the same ability that created the token and set its other characteristics). That's actually a 95% approximation (an intrinsic ability is actually an ability that's part of the set of copiable values for an object) but it'll get you through most situations, and intuition will help you with the rest: a CDA setting power and toughness on a Maro is still a CDA when you've copied it onto a Clone.
• CDAs only apply to the object they're on—An ability that does something to a card and several of its bretheren, like the one on Uborg, Tomb of Yawgmoth, isn't a CDA. An ability like the one on Kobolds of Kher Keep, which identifies itself by name, is.

Those are the bits that haven't changed. They don't address the question of what a CDA does, as that's one of the things that changed. So on to the new stuff:

• CDAs set particular characteristics—Rule 405.2: "Some objects have intrinsic static abilities that define the object's colors, subtypes, power, or toughness. These abilities are characteristic-defining abilities". Now, "having a particular ability" is a charateristic, but the ability that grants the ability is no longer special. In the old rules "~this~ has flying" was a CSA, but "~this~ is indestructible" wasn't, since indestructible isn't an ability. This was confusing, obviously. So the new CDAs do away with that distinction, and neither ability is a CDA. Plus, while it's obvious that a creature with */* for power and toughness needs some special help, it's not obvious at all that "~this~ has flying" deserves special treatment.
• CDAs function everywhere—CSAs have gone through some evolution about what they did in other zones as cards were printed that cared about characteristics of cards not in play. Most recently, CSAs would operate in non-play zones only if they affected type or color. CDAs function in all zones. The big change here is for cards with CDAs that set their power and toughness, like Maro or Nightmare, which now have non-zero P/T in your hand or the graveyard. Sutured Ghoul just made some new friends.
• CDAs aren't subject to dependency rules—This is getting into the technical stuff. CSAs in the layer system described in 418.5 were applied before non-CSAs in their layer, unless the CSA depended on another effect, in which case its CSA-ness was ignored. CDAs are always applied before non-CDAs. This means that Humility will no longer overwrite layer 5 CDAs (like color-setting CDAs).

The bottom line is that CDAs are a more pure and more intuitive implementation of the original concept: they're special abilities that change how a card would be printed. We'd like to have cards with no mana cost that are still colored, or that have non-fixed power and toughness.

A third and fairly technical change involves the removal of one of the most confusing rules in the entire Comprehensive Rules document, reprinted here for your enjoyment:

500.5. When determining what requirements could be obeyed without violating restrictions, you don't need to consider any options for a creature that don't satisfy a requirement on it. But you do need to consider any options for any creature(s) that will satisfy a requirement, as long as the total number of obeyed requirements is increased (even if the option means not obeying another requirement that was previously met).

Got it? Good. Now you don't have to obey that rule anymore.

Okay, I was serious when I called it one of the most confusing rules in the game. What this rule did was prevented an attacking or blocking requirement on one creature from imposing an indirect requirement on another creature. So if Two-Headed Sliver and Hunter Sliver are in play, and a Sliver attacks and Provokes another creature, under the old rules, the defending player wasn't required to find another creature to block along with the Provoked creature. Under the new rule, you'll be required to find a block that satisfies the Provoke requirement. Either outcome is reasonable, but the elimination of such confusing verbage can't be a bad thing for the game.

These rules changes are of more interest to judges than players, but it's still good for all of you to be at least somewhat aware of what's going on behind the long, complicated rulings that you're torturing your Pro Tour Qualifier head judge with. They also mean that a good number of rulings in our database are out of date. Chris Richter and I haven't yet come up with a strategy to deal with that—there are over seven thousand questions in the SCG database!—but we'll be working on a solution in the near future.

Next week brings us back around to Nick Fang, which is always something I look forward to. Until then, keep shufflin'.