Modified cards and their tournament legality

[Lofobal]

I was wondering how much one can draw on a card before it is no longer legal to play said card in a tournament (assume I'm using completely opaque sleeves, so markings on the back of a card should probably be irrelevant). Which features of the card must be distinguishable?

1. the name
2. the casting cost
3. the art
4. the card type
5. the power/toughness (for creatures only, obviously)
6. the expansion symbol, border, et cetera

It seems as if a card could be legal if the only distinguishable features on it were the name and casting cost, taking the recent textless promotional cards as an example.

It also seems as if a card could be legal if only the art was distinguishable (such as the Pyrite Spellbomb in Hi-Val's recent Star City Games article), considering that art is unique to each card (with the exception of some Chinese cards, due to the laws concerning the censorship of human skeletons in China). As long as the owner knows what the card is and what it does, this doesn't seem too different from a card in a language which no one in the immediate vicinity can understand.

The card type and power/toughness can be looked up in the Oracle, but this would be tedious and time-consuming, particularly if many of a players cards were missing this information.

I included the final point due to City in a Bottle variants; if I, for example, draw in green sharpie on the border of a Kird Ape, and draw over the expansion symbol and the copyright information et cetera, how would anyone know whether it dies to City in a Bottle or if it's from Revised. I'm aware that the revised one is lighter, but it could simply be a faded Arabian Nights one. I'm also aware that this situation is rather obscure, but I'm trying to learn all the details concerning the legality of cards.

I have questions concerning the physical shape of a card as well. Is it legal if a card has
1. cut off corners
2. objects pasted onto it
3. indentations
4. one or more holes in it
5. a tear
Assume for all of these that the player is not touching his or her deck frequently, nor that the markings are visible through an opaque sleeve, eliminating the possibility of marked cards. I make a note of the player not touching his or her deck frequently, as this is already somewhat illegal due to the presence of foiled cards.

My initial thought on the corners was no, but in light of the ruling on Alpha cards, I'm not sure why they shouldn't be allowed when opaque sleeves are used, so long as they are minor.

I'm quite sure that having any object pasted to a card makes it illegal, as it changes the thickness of the card, thereby marking it. Despite this, I wanted to ask, just to ensure that my thinking is correct. (Pasted objects would include, but not be limited to, paper, whiteout, other art supplies and foiling peeled off other cards).

By indentations I mean those which might be caused on the back of a card by pressing too hard with a pen on the front. I assume cards with these marking would be illegal, but they're not much more identifiable than foil cards through opaque sleeves. Holes are simply an extension of indentations and included for the sake of completion; I assume cards with holes would not be allowed.

Tears seem as if they could be legal or illegal depending on the size of said tear. Note that by tears I mean not only full tears (such as those which might be something like scissors), but also shallow tears (such as a card which is missing the front half of the bottom quarter of the card, and is therefore thinner on this bottom quarter).

I apologize if this post is a bit long, but I wanted to ensure I received all the facts concerning this rules issue. I searched carefully, but unsuccessfully, before posting this. Thank you in advance for your help.
For reference, this is the aforementioned article by Hi-Val which inspired these questions.

[Jacob Orlove]

130.   Marked Cards
This section deals with marked cards or sleeves. As always, the penalties for these infractions assume the infraction was unintentional. If the head judge believes the markings are intentional, he or she should refer to section 160, Cheating.

131.   Marked Cards—Minor

Definition
A player's cards are marked in a way that is disruptive but unlikely to give an advantage to that player. (If the player is using sleeves, the cards must be examined while in the sleeves to determine if they are marked.)

Examples
(A) A player in a Magic tournament has small marks on a few of his sleeves. The markings are on an island, a Counterspell, and a Masticore.
(B) A player without sleeves has several premium cards that stand out significantly from the rest of her deck.

Philosophy
If the possibility for advantage is fairly low, the player should be required to replace the card(s) or sleeve(s) but should not receive a significant penalty. Note that almost all sleeves can be considered marked in some way; judges should keep this in mind when determining penalties. In cases of marked cards, educating players to shuffle their cards before sleeving them is very important.

Penalty
Marked Cards—Minor
REL 1   REL 2   REL 3   REL 4   REL 5   
Caution   Caution   Caution   Warning   Warning   

132.   Marked Cards—Major

Definition
A player's cards are marked in a way that could potentially give a significant advantage to that player. (If the player is using sleeves, the cards must be examined while in the sleeves to determine if they are marked.)

Examples
(A) A player in a Magic tournament has a marking on each of his land cards that makes them easily distinguishable from the rest of the deck.
(B) A player in a Magic tournament has four Upheavals in her deck, all of which are in card sleeves that each have a slight bend in one corner.

Philosophy
If the possibility for advantage is high, the player should receive a significant penalty. Please note that this penalty still assumes that the cards are marked unintentionally. If the head judge believes the cards were marked intentionally, he or she should refer to section 160, Cheating.

Penalty
Marked Cards—Major
REL 1   REL 2   REL 3   REL 4   REL 5   
Game   Game   Match   Match   Match   

Cards used in a tournament may not have writing on their faces other than signatures or artistic modifications. Modifications may not obscure the artwork so as to make the card unrecognizable. If modifications to a card are deemed by the head judge to constitute outside notes or unsporting contact, the owner of the deck are subject to the appropriate provisions of the DCI Penalty Guidelines.

[Hi-Val]

For reference, I have never had a judge say that any of my cards are illegal, outside of the obvious stuff like blacked out cards and that janky crop rotation, which I wouldn't play anyway. For modification's sake, I make sure that the art is still there for tournament cards and that the title is there for safety as well.

If I were concerned and I wanted to play the card, I'd consult the head judge before the tournament began to see if it was legal. If it wasn't, I'd swap the cards out for unmodified ones.

[Cross]

What about differences in the thickness of cards. Particularly if someone were to apply a sticker to the card, thus changing the card’s thickness, is the card still legal for tournament play? Does this just apply under the marked cards ruling, or is there a special case for this. This does make reference to premium cards, I'm assuming they mean foil by this, so would this be the same case?

Also, similar to this, I have heard stories about judges being very particular about players touching their decks for no reason because if you riffle through the side of your deck you can tell the difference between the thickness of foil cards versus non-foil and therefore gain knowledge of where these cards are in your deck. Is this true? And what about general touching your deck issues? Like, what if as a nervous habit you riffle the corners of your deck, or if you are one of those players that constantly makes sure the deck is stacked in a perfect rectangle.

[epeeguy]

As Jacob has already pointed out, there is the "by the book" answer to the question here.  At a minimum, a person (whether the player, that player's opponent or a judge) must be able to make out what the card is based on its artwork.  The reason is obvious; regardless of the language of the card, this is the one unique characteristic that never changes.  So, by obscuring the artwork, it becomes difficult to identify the card by any other means.

Speaking from experience, it's not a good idea to obscure the rest of the card and leave only the artwork visible.  Since most of the time people still need to read the rules text of the card, or the name of the card (since they may not recognize the artwork), blacking those two pieces out are not helpful either.  Neither would be covering over the power and toughness of the card (if it were a creature).  So, in practice, there's even less you can do to a card in order to keep it "legal" (at least in some judges' opinions).

As for things that might change the thickness of the card and make it more readily identifiable... that would be a problem as well.  Especially if someone was apparently "feeling" their deck.  So, that would definitely not be good either.  The same goes for deck sleeves as well; some of which could be marked in such a way to identify them just by feeling the edges.  If it was just done for "fun" and was artistic in nature, that might be discouraged (but not penalized).  If done for the other reasons... obviously that could fall into the category of Cheating.

But, in general, marking up the card to the point where it is difficult to make out is discouraged.  As would be doing anything to the card that could potentially be "abused".

[rvs]

It's up to the headjudge. Just be sure to ask him on beforehand.