The Mammoth's Jump — Next Gen Shapes #1

The Next Gen Shapes Series

There's nothing new under the sun. But, at the same time, the post-AI era seems to emphasize different enough shapes for us to maybe feel like they're new.

In this series, we'll explore some of them. Most have been spotted and catalogued by much stronger players than me, but this first one I haven't spotted anyone mentioning yet.

The following explanations haven't been checked by any professional players, they've mostly come from my experiences and interpretation, as a Fox 6-7d player, at most I have briefly commented about them to friends and colleagues of similar rank.

So bear with me through the future improvements this article will inevitably need and receive. And, if you feel like you have something to add, please do so in the comments below or through direct messages with me.

The Mammoth's Jump

The "Mammoth's Jump" is exemplified in Dia. ?, in a game between Kim Eunji 김은지 9p (Black) and Lee Jihyeon 이지현 9p (White), played on September 20th, 2026:

The shape between 1 and A is similar to the "Elephant's Jump" , hence the overly creative name for the "new" shape. Would people prefer "Big Elephant's Jump" instead? An ohazama tobi perhaps?

The middle point between A and B in Dia. ? is known as the "Elephant's Eye", and is usually a major weakness, since it splits A from B. However, with proper setup and good direction, White 1 could backfire into a less meaningful, slow, or even dangerous poke. After all, it's a move in between two outside opposing stones, which doesn't generate any shape or points by itself.

In almost all cases, Black would like to avoid trying to block the splitting stone too tightly, as it doesn't work, and essentially only creates a broken keima between 1 and A:

In general, it's better technique to jump ahead with a keima, as in Dia. ?, staying ahead of the opponent, allowing us to then spend our turn to defend the A stone with B, or perhaps try fights or compromises with C.

The Mammoth's Jump, as I see it and as far as I was able to investigate, is just a variation on the logic behind the Elephant's Jump.

With A a little bit further away, as in Dia. ?, when playing moves such as 2, there's less direct damage to A when White breaks through.

Again, it's worth emphasizing that neither the Elephant's Jump nor the Mammoth's Jump make much sense without the appropriate context.

In the game example we've briefly inspected above, Black has quite a few reinforcements backing one side of the Mammoth's Jump, and that's not even mentioning that the bottom-right context of a lone White stone might be even more relevant:

AI suggests that Black should be willing to sacrifice the A stone in the center, the stone which originated the Mammoth's Jump in the first place, in order to take strength and potential profits against White's B stone and the right side.

Lee Jihyeon 9p (White)'s thought process is not available to me, nonetheless I suppose he didn't poke through because, not only does it damage B, it's a slow move in the center — a kosumi is typically very slow in general, not only in this context. In the game, he opted for the pretty shape of C.

Unexpectedly, though, 32 in Dia. ? is AI's recommendation for White still, with C losing almost a point, or around 11% in win rate.

Circling back to the appropriate context theme, the "feels-good" A cap in Dia. ?, in the middle, in the beginning of the game is typically too vague for AI. White's group on the left is not weak enough to justify a center move at this point in the game. The loss is small, of course, and Kim Eunji 9p (Black) probably chose it anyway because it fits her fierce style of play. To the AI acolytes out there, as Alexandre Amaro Fox 7-8d would say, A feels like a gamble.

AI would rather kick White's stone in the bottom-right, while showing a beautiful display of flexibility in response, diving into the 3-3 right way:

Moyo Development with The Mammoth's Jump

The Mammoth's Jump is admittedly very niche. No wonder, this article is likely the longest essay on it to this day if not for a very long time — or forever, though that's also a very long time. But the point in studying it is to generalize the underlying, related techniques to other areas of the game.

And one such area is connected to moyos. Sometimes, the Elephant's Jump can be an amazing tool for defending moyos:

Both Black and White are trying to expand their moyos, with the influence-collision area being around A. With 1 on Dia. ?, Black aims at skipping one step further than A, while also reserving the possibility of turning that move into more of an invasion or reduction, rather than a moyo expansion.

If White tries to get in, Black will switch to defending the right side, dealing with the lone Black group in the center separately, and, at the same time, forcing White into creating an empty triangle with the 2-4-6 shape: