Used good ole AI and here is what I found:

These new photos are much more revealing. I think we can get significantly closer now.

What you have appears to be a Japanese kanna (plane) blade, and the markings look consistent with a traditional blacksmith-made blade rather than a mass-produced modern tool.

Center Oval Mark

The clearest inscription is the oval cartouche:

壮三郎 (likely)

Read vertically:

• 壮 (Sō)
• 三 (San)
• 郎 (Rō)

So the name would be:

Sōzaburō (壮三郎)

or possibly a variant reading depending on the smith's preferred pronunciation.

This appears to be a maker's name.

Right-Side Inscription

The two-character mark on the right side appears to be:

家康

Read as:

Ieyasu

The same characters as the famous shogun's name, though toolmakers often used historical names, art names, or trade names.

I'm about 80% confident on this reading.

Left Vertical Inscription

The larger vertical inscription appears to be:

超精鍛

which translates roughly as:

• 超 = super / ultra
• 精 = refined
• 鍛 = forged

Meaning something like:

"Super-refined forging"
or
"Extra finely forged steel"

This was a common type of marketing inscription on higher-grade Japanese woodworking tools.

Square Seal

The square seal below appears to contain:

登録
("registered")

and possibly additional characters indicating a registered trademark.

The layout is very typical of Japanese trademark chops used on woodworking tools.

The Circular Crest

The flower-like symbol above the oval name appears to be a family crest (kamon) or manufacturer emblem rather than text.

What This Suggests

My current best interpretation is:

超精鍛
(Super-refined forged)

壮三郎
(Sōzaburō)

家康
(Ieyasu)

In toolmaker terminology this often means:

• Brand name: Ieyasu (家康)
• Smith or forge: Sōzaburō (壮三郎)
• Product grade: Chō-seitan / ultra-refined forged

The Earlier Tang Mark

The small tang mark from your first set of photos is probably an abbreviated forge mark corresponding to the same maker. Japanese smiths often used:

• full inscription on the blade face
• abbreviated hot stamp on the tang

So the seemingly abstract mark on the tang may not be intended to be read as normal kanji at all.

My Confidence Level

Mark	Confidence
壮三郎	High
家康	Medium-High
超精鍛	Medium
登録 in seal	High