I’m not going to mention the source where the info leaked from, but I've been using it for months and I can tell you it works!

Did you know you can rank any position you want?

 Ranking first with rank meta tag

Add this meta tag to your page, Fetch as Google, Submit to Index, wait for googlebot to crawl your page, and enjoy top ranking!

To rank #1 for any keyword, on any SERP:

<meta name="rank" content="1" />

To rank #1 for the keyword “seo software”:

<meta name="rank" content="1;seo software" />

To rank #1 for the keyword "seo software" on google.co.uk only:

<meta name="rank" content="1;seo software;google.co.uk" />

To rank #1 for any keyword on google.co.uk only:

<meta name="rank" content="1;;google.co.uk" />

The tag can be repeated several times to specify different SERPs:

<meta name="rank" content="1;seo software;google.co.uk" />
<meta name="rank" content="1;seo software;google.com.au" />

The specified rank value can be any integer, not only 1.

And what if more than a candidate page sports the rank meta tag, with the same content value?

In that case, they would be sorted based on their normal ranking. An unintended feature is any integer value is accepted, even negative.

Using for example -1, we would rank before any page having rank meta tag with content="1":

<meta name="rank" content="-1" />

It works a little like the CSS z-index does, but the lower, the higher in the SERP:

<meta name="rank" content="-100" />

...except that when you use a negative value, and no other page is, your result does not show up!

Digging a little into the issue, I've seen it actually appear in the HTML, but the snippet is CSS positioned above the top zero coordinate!
Weirdly, a value of zero seems to be ignored.

Try it out before they fix it!

The trick didn't last long; it seems they fixed it. I bet they had no time enough for a full fix, they probably just worked it around by renaming the meta tag. I hope someone will experiment a little further to find out how.