For years I have read about the various attempts to add a colourless 'Basic Land' to Magic.

This is my version of a possible solution. It isn't basic so it avoids all the issues adding a sixth basic land type would cause but you can have any number in your deck just like a regular basic land. It is a Pseudo-Basic Land. It does have a land type - Cavern so that in the extremely odd/rare case you could give a creature cavernwalk but as it isn't a basic land it doesn't count as a basic land type.

This is in no way meant to be printed, it is just my attempt to solve an ongoing dilemma of the game. Even I doubt that this would actually work as it 'should' so any Ideas/comments/thoughts/etc would be welcomed.

You can see my effort at: http://multiverse.heroku.com/cards/1253 :)

If you don't require a basic land type it's easier -- I agree this almost works for that. (I think you could also have "basic land -- cave" but have cave not be a basic land type, which also allows "search for a basic land card" to work)

The sticking point for me is that currently the card is really useful in colourless highlander decks, which really need a colourless basic land, but elsewhere is strictly worse than a normal land, whereas I want it to have some advantage, but I'm not sure what advantage would make sense on a basic land. Any small bonus would feel semi-arbitrary, and some wouldn't work in large numbers.

Hm. The recent Sejiri Refuge cycle make me wonder if a colourless basic land could have "When ~ ETBs, gain 1 life" on it.

Yeah, I think I considered that as well. It looks about right: a small bonus, but one you're happy to have (especially if you have lots of land, it would be amusing in a green/colourless deck, if you can just keep dumping multiple lands a turn :)) And simple, enough that it could be canonical version. I'm worried having lots of those might be too much, but probably not, given that many lands do that already (the same as a single Glimmerpost, except that you can have more than 4 of them, but they never go exponential)

Or maybe, "T: add {1 1/3} to your mana pool", like toned down urza's lands :)

You could add a rider on it so that it can be searched for as a basic land so that Rampant Growth etc can find it couldn't you?

Or just make it a basic land and remove the type so instead of "Land - Cavern" it had "Basic Land", then you wouldn't be adding a new Basic Land type?

Hmm... I understand why one wouldn't want to create a sixth basic land, but I don't know why this land would need to be created. What niche does it fill? I get the "Make Caverns Matter" concept that was alluded to with Cavernwalk, and I could definitely see a block similar to the one alluded to in the Great Designer Search 2, where non-colored mana is needed for certain spells. But unless 20 or so cards are designed around Cavern, I can't see why someone would put this card in their decks. This seems like a solution to an argument that neither side likes, since the people who are arguing for a 6th basic land understand that it breaks certain cards. That's why they like it.

It makes it a lot easier for Karn EDH decks to fill out their mana base, and...that's about it.

Yeah. There is no actually persuasive reason for this to exist (which is presumably why it doesn't). I saw it originally suggested by Mark Rosewater (http://www.wizards.com/magic/magazine/article.aspx?x=mtg/daily/mm/25) as a sixth basic land type for increading the effect of domain spells. But most people want to do it because we like ridiculous challenges, especially conceptual challenges, and like symmetry :)

I agree with Jack V. I think it is just the challenge of creating something like this that works in the game without screwing up the basic land system totally. I also saw this in the same MaRo article and have considered taking a crack at it as I love puzzle solving.

It needs to be slightly better than the coloured lands though; since they can always substitute for it, but it can't substitute for them. Can't be much though.

The last time I tried that, I ended up with "~ ETBs untapped" ; realised that was ridiculous slapped it onto joke card and gave up.

Good luck!