It is the absence of red

What everybody says

Open any guide to this card and you will find the same sentence. An authentic O-Pee-Chee Gretzky rookie has a yellow print dot on his left shoulder. Every card in the run has it. If it is missing, walk away.

All of that is broadly true. The explanation underneath it is not.

No yellow ink was added

Look at the jersey. It is orange.

Orange is not an ink on a four-colour press. It is yellow with red printed over it. Lay the red down on top of the yellow and the eye reads orange.

Which means the mark on his shoulder is not something that was added. It is something that was missing. In that one spot the red never reached the paper, so what shows through is the yellow that was already there, underneath, across the whole jersey.

The dot is a hole in the red plate's coverage. The yellow was there all along.

Why it is on every single card

This is the part that makes it useful rather than merely interesting.

A loose particle on a press blanket usually has a short life. It falls off, or it is cleaned away, and the fault appears on some sheets and not others.

This one is on every authentic example, in the same place. Which tells you it was not a stray speck sitting on a blanket for a few hundred impressions. It was in the plate or in the film the plate was made from: fixed, and reproduced faithfully on every sheet that ran.

So a production fault that ought to have been invisible to history was instead stamped identically onto the most valuable hockey card ever printed, hundreds of thousands of times.

Does the Topps card have one?

Here the sources disagree and we are not going to pretend otherwise.

Two widely used guides state flatly that the Topps version has no print dot, and use its absence as one way to tell the two apart.

A third says that for the record the Topps version also carries a small yellow line in the same area.

Those cannot both be right. Our reading is that if you are using the mark to distinguish O-Pee-Chee from Topps, you should not rely on it alone, because at least one experienced source says the distinction is not as clean as it is usually stated. We have written about the differences that are not in dispute, and the bilingual back is the one that settles it in a second.

And it is no longer proof of anything

The dot became the standard test for a good reason. Most counterfeits of this card are photographs of photographs, and fine detail degrades with every generation of copying. A small yellow blemish on a shoulder is exactly the sort of thing that disappears.

That logic held for years. It does not hold now.

Beckett's own guide records seeing a counterfeit O-Pee-Chee that did carry a smaller yellow dot. Another long-running guide puts it as a warning in capitals: some counterfeits contain this dot too.

Which is what you would expect. Once a tell becomes the first thing every buyer checks, it becomes the first thing a forger reproduces. A test that everybody knows is a test that somebody has already beaten.

What to check instead

Four things, none of which is defeated by copying an image.

Solid ink under a loupe. On an authentic card the lettering of the name and the team is solid ink, sharp and smooth. On a copy of a copy it breaks into a pattern of small dots, and the black border pixelates where it should be continuous.

The back, in two languages. O-Pee-Chee printed for Canada, so the reverse carries English and French throughout. Topps is English only. A counterfeiter working from an image of the front has to get the back right as a separate job.

The stock itself. O-Pee-Chee stock is brighter than Topps and fluoresces noticeably more under a blacklight.

And the edge. Authentic examples are usually rough, because of how O-Pee-Chee cut them. A suspiciously clean edge is worth a second look on this issue.

One more disputed mark, while we are here

Some authentic examples carry faint blue lines running vertically down the back.

The belief among some collectors is that these indicate a first print run, and people will pay more for them on that basis. One guide notes plainly that there is no concrete evidence for the claim, and that the question has been argued for years without resolution.

We would treat a blue-line premium the same way we treat the yellow dot: an interesting characteristic, not an established fact, and certainly not something to pay extra for on the strength of folklore.