All Yokoyama plane blades are forged using pine charcoal. Charcoal smithing is the best because the low heat prevent the carbon evaporation. But at the same time it is the most expensive method as well, so not many blacksmiths forge this way. Some blacksmiths claim their planes are charcoal smithed but in reality gas forge smithed.

The dai is made by master dai maker Nimura-san. As you can see very closely grained high quality Japanese white oak. This white oak is the best from Sonobe, Kyoto. BTW, red oak is the best from Miyako-no-jyou, Miyazaki.

36mm Housen on the right. Size comparison with Sun-hachi size (70mm) Yokoyama "Kuni" Reigou plane. This Housen is the plane I'm using in the quince chisel handle making.

Housen 36mm on the right, Kuni 70mm on the left.

Using the same high quality kamaji for the smaller blades as well.

Kanshin 36mm Blue Steel #1 koganna (small plane) by Yokoyama Kunio (Regular Price $165)

36mm double blade koganna. Dai is made by Nimura-san. You can see how close grained this oak is. Nimura-san uses the best white oak material from Kyoto.

Kanshin

It is basically invisible but the jigane is kamaji. Easier to sharpen.

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Kanshin means to observe your heart.

Yagyu Tajimanokami, the swordsman who influenced Musashi the most, teaches that
if one is too eager to kill the opponent, one will cease to flow, thereby lose the chance to
move. The final esoteric teaching of this Yagyu school is just two Kanji character Sui-getsu
(Moon reflecting on the water) meaning "the water reflects the moon without any thought. One
needs to let oneself flow and just react."

There was an animal called "Satori" and this animal can read human mind.
One day a man was collecting firewood in the woods when this animal appeared and
told him, "You are wondering what I am doing watching you." The man was surprised.
The animal went on "Now you are surprised and wondering why I knew what you are
thinking." The man got scared and thought of killing this animal. The animal told him
"I can read your mind, how do you figure you can kill me?" The man tried all the same
to kill this animal but in vain. The man gave up and decieded to finish gathering the firewood
and go home. As he raised his axe to chop the branch, the head of the axe flew off
and hit the animal to death...

Kanshin means kind of like that(^^)

Yokoyama Plane Blacksmith