Reverse Engineering & Archaeology to Make a Seigen Maple Bonsai

Two of my favorite bonsai are Musashi Ga Oka and Koga from the Omiya Bonsai Museum. What I find so interesting about them is the dramatic difference between the size of their root base (nebari) and their relatively thin trunks.

In 2024 I spent a suspicious amount of time with these trees, getting my hands and eyes as close as possible under careful supervision.

Here is Musashi Ga Oka:

 

And here is Koga:

 

Those thin trunks did not create those massive bases on their own. In fact, a closer look reveals that a great number of ‘trunks’ contributed to those bases — which still bear the scars and discolorations to prove it (please note that the trees were wet when I visited)

I don’t have 180 years to make something like Musashi Ga Oka or Koga. Don’t get me wrong — I have started projects that won’t be 'finished' in my lifetime, and I think it’s important for all of us to be doing that.

However, seeing the kind of Japanese maple bases that Mr. Ebihara was able to develop in just three short decades suggests that perhaps I can get closer to my goal than I thought, within my lifetime.

If you've never heard of Ebihara before, once again let me refer you to the Bonsainut forum as a good starting point: click HERE

So here is a sketch I drew in 2018:

 

The idea is as simple as it looks!

Step 1

Start creating a massive, sprawling base like Mr. Ebihara did, using one trunk.

Step 2

At some point during that process, graft additional trunks into that base.

Step 3

Once those grafts can keep the base alive reliably, gradually remove the main trunk (using another technique popularized by Mr. Ebihara: 'notch cutting').

Step 4

Keep growing the base as wide as possible, adding additional grafts/trunks as needed.

Right now, I’m at Step 2 with this project.

I developed this trunk and base using one of the most vigorous Japanese maple cultivars I have: ‘Yves’ Select’.  This cultivar was selected by Mr. Yves Létourneau, who purchased seeds from J. D. Vertrees in 1986, planted them in 1987, and eventually selected this strain among the 400 seedlings that emerged.

The grafts? You guessed it: Seigen!

The goal would be something like this:

Note 1: there is some degree of urgency when it comes to adding the first grafts, because at some point the main trunk will create a wound that is far too large to manage predictably.

Note 2: these new grafts might not necessarily become the trunks of my 'final' design. They’re quite close together and, like the original trunk, they too might eventually get overly thick for the design. But I decided to use Seigen just in case any of these trunks stick around for a while.

Take a look at these maples below.  I don’t know how these trees were developed really, but they look like they could have been developed this way.

In my imagination, the first one shared by Mr. Taiga Urushibata (who apprenticed at Mr. Masahiko Kimura) could have had its central trunk removed.  By contrast, in the second image the main still trunk remains but it could be removed/replaced if the goal was to eventually create something like Musashi Ga Oka.

 

(second pic forgotten source, if you know the origin let me know)

I think it is helpful to imagine trees like these as a natural step on the way to developing something that will eventually look more like Musashi Ga Oka or Koga.  But I only mean that as a thought experiment, because either of these trees can be 'held' and refined in this status too — why not?  They're perfectly fine!

When it comes to planning the futures of our bonsai the tension between satisfaction and sacrifice is usually represented by an equal opposition of synchronic and diachronic perspectives.

I listed 4 steps above.  This would be Step 5 (repeat as/where needed):

To pursue my dream, grafting trunks near the perimeter of the base will help to widen it.  Below is a maple I visited at S-Cube, where this very technique is being used to develop the base of this single-trunk design.

 

I’ll share follow-ups as things progress on my journey towards creating a base whose mass is inexplicable by the trunks above it alone.

A final note: I don't think that this is the only way to create something like Musashi Ga Oka and Koga.  The more straightforward way is to plant multiple trunks near each other and wait for their bases to fuse.  I have many projects that I've started this way too.

In this scenario the original trunks can eventually be replaced with much thinner trunks once they have done their work if, like me, you're fascinated by the prima facie absurdity of big bases and pencil trunks.

This blog post is about testing things out with one trunk because I was fascinated by Ebihara's relatively rapid progress.  In principle, Ebihara's method could be applied to an infinite number of neighbouring trunks which would eventually fuse together, creating an infinitely wide nebari...