Quick Summary:
- Your grandfather's WW2 Japanese sword is either a $200 showato (machine-made) or a $5,000+ gendaito (traditionally forged). Knowing the difference changes everything.
- The key identifier is the hamon (temper line): real hamon from clay-differential hardening vs. fake hamon from acid etching or wire brushing.
- NBTHK will not certify showato. Only gendaito qualify as authentic nihonto.
- Our recommendation: before polishing or selling, get a proper identification from a specialist.
Table of Contents
- What is a showato?
- What is a gendaito?
- How to tell the difference: step by step
- The hot stamp guide
- Can NBTHK certify a showato?
- What is your WW2 sword worth?
- Should you polish a gunto blade?
- FAQ
Your grandfather's WW2 Japanese sword is either a $200 wall-hanger or a $5,000+ collector's piece. The difference comes down to one question: is it a showato or a gendaito? Thousands of WW2 Japanese military swords (gunto) came home with Allied soldiers after 1945. Some contain mass-produced blades stamped out of industrial steel. Others hold traditionally forged nihonto made by licensed swordsmiths using tamahagane. This guide shows you exactly how to identify which one you have.
What is a showato?
A showato (昭和刀, literally "Showa-era sword") is a machine-made blade produced during Japan's wartime mobilization, roughly 1933-1945. These blades were manufactured from modern industrial steel using power hammers, hydraulic presses, and oil quenching. They were never folded. They contain no tamahagane. They are not nihonto.
Japan needed millions of swords for its expanding military and could not produce enough traditionally forged blades to meet demand. Factories in Seki (Gifu Prefecture) and Toyokawa (Aichi Prefecture) churned out showato by the tens of thousands. The steel was typically spring steel or rail steel, heat-treated in oil rather than clay-quenched in water.
Showato served their purpose as military sidearms. But from a collector's perspective, they have no metallurgical or artistic value as Japanese swords. They are WW2 military artifacts, nothing more.
What is a gendaito?
A gendaito (現代刀, "modern sword") is a traditionally forged blade made by a licensed swordsmith using tamahagane steel and classical methods: smelting in a tatara furnace, repeated folding and welding, clay-differential hardening in water. Gendaito are real nihonto by every technical definition.
During the war, established swordsmiths like Gassan Sadakatsu, Kasama Ikkansai Shigetsugu, and Ichihara Nagamitsu continued forging blades the traditional way. Their work was mounted in standard military gunto fittings, making them look identical to showato from the outside. But the blades inside are authentic, traditionally made Japanese swords.
A wartime gendaito by a known smith with NBTHK certification can fetch $5,000 to $15,000 or more. Some exceptional pieces by top wartime smiths have sold for over $20,000.
How to tell the difference: step by step
The gunto mountings (shin-gunto, kyu-gunto, or kai-gunto) tell you nothing about the blade inside. Both showato and gendaito were mounted identically. You must examine the blade itself. Here is the process, in order of reliability.
Step 1: Look at the hamon (temper line)
This is the single most important test. A gendaito has a real hamon created by clay-differential hardening: the smith coats the blade in clay, leaving the edge thinner, then quenches in water. This creates a visible boundary between hard martensite at the edge and softer pearlite in the body.
How to check: hold the blade under a single bare incandescent bulb (not fluorescent, not LED). Tilt the blade slowly. A real hamon shows:
- Crystalline activity along the temper line: bright sparkling particles called nie (沸, visible crystals) or a misty glow called nioi (匂, too fine to see individually)
- Variation in the pattern: no two inches of a real hamon are identical
- Depth: the pattern appears to exist within the steel, not on the surface
A showato has either no hamon at all or a fake one. Fake hamon come from two sources:
- Acid etching: the blade is dipped in acid to create a visible line. It looks flat, uniform, and has no crystalline activity
- Wire brushing: a pattern is scratched onto the surface. It disappears with polishing
If the hamon looks like a printed line with no depth or sparkle, it's a showato.
Step 2: Examine the jihada (grain pattern)
Traditionally forged blades are folded multiple times, creating visible layers in the steel called jihada (grain pattern). Under good light, you can see patterns like itame (wood grain), masame (straight grain), or mokume (burl grain).
Showato steel was not folded. The surface looks flat, featureless, and homogeneous, like a piece of modern tool steel. No grain. No texture. No life.
Caveat: a heavily rusted or poorly polished blade may hide the jihada on a genuine gendaito. If you can't see grain but suspect the blade might be traditionally made, do not attempt to clean it yourself. Seek a professional opinion.
Step 3: Check the tang (nakago)
Remove the handle (tsuka) by knocking out the retaining peg (mekugi). The tang often holds crucial information:
- Signed tang (zaimei): A gendaito by a licensed smith usually bears the smith's signature (mei) on the tang. Research the name. Cross-reference with known wartime smiths.
- Serial numbers: A tang with only a stamped serial number (no brush-style signature) is almost always a showato.
- File marks (yasurime): Traditional smiths file the tang in distinctive patterns. Machine-made tangs have uniform, mechanical file marks or none at all.
Step 4: The steel test
Gendaito are made from tamahagane or oroshigane (re-smelted traditional steel). Showato use modern carbon steel, sometimes called mashigane. The distinction matters because mashigane was mass-produced industrial steel, while tamahagane comes from a tatara furnace processing iron sand.
Under proper lighting, tamahagane steel has a warmth and liveliness that modern steel lacks. The surface shows subtle color variations and activity. Machine-made steel looks cold, flat, and monotone. This is admittedly subjective and takes experience, but once you've seen both side by side, the difference is unmistakable.
The hot stamp guide: arsenal marks and star stamps
Many WW2 Japanese swords carry hot stamps on the tang or blade. These are arsenal inspection marks, not maker's marks. Here is what they mean:
| Stamp | Meaning | Location |
|---|---|---|
| Star (☆) with Seki (関) | Seki Arsenal, Gifu Prefecture | On tang |
| Star (☆) with Toyokawa | Toyokawa Naval Arsenal, Aichi Prefecture | On tang |
| Star only (no kanji) | General military acceptance mark | On tang spine |
| Showa (昭) + number | Year of manufacture (e.g., 昭18 = 1943) | On tang |
| Seki stamp alone | Produced in Seki district | On tang |
Critical point: the star stamp does not tell you if a blade is showato or gendaito. Both types were inspected and stamped at the same arsenals. A star-stamped blade could be either. You still need to examine the steel, hamon, and jihada to determine what you have.
Can NBTHK certify a showato?
No. The NBTHK (Nihon Bijutsu Token Hozon Kyokai) only certifies traditionally forged Japanese swords. A showato submitted to shinsa (appraisal) will be rejected because it fails the fundamental requirement: it was not made using traditional materials and methods.
A gendaito, on the other hand, absolutely can receive NBTHK papers. Wartime blades by known smiths regularly achieve Hozon ("worthy of preservation") status, and exceptional examples have earned Tokubetsu Hozon ("especially worthy of preservation"). Having NBTHK papers on a wartime gendaito dramatically increases its market value, often by 30-50%.
What is your WW2 sword worth?
The value gap between showato and gendaito is enormous. Here are realistic 2026 market ranges:
| Type | Price Range | What Drives Value |
|---|---|---|
| Showato (standard) | $150-$400 | Blade condition, fittings completeness |
| Showato (excellent fittings) | $400-$800 | Original tassel, matching numbers, rare unit markings |
| Gendaito (unsigned/unknown smith) | $2,000-$4,000 | Blade quality, condition, attribution |
| Gendaito (known smith, no papers) | $3,000-$8,000 | Smith reputation, blade condition |
| Gendaito (known smith, NBTHK Hozon) | $5,000-$15,000+ | Smith, certification level, blade quality |
The military fittings (gunto koshirae) carry their own value separate from the blade. A complete set of shin-gunto fittings in good condition with original tassel and scabbard can be worth $200-$600 regardless of the blade inside.
Should you polish a gunto blade?
Do not polish anything until you know what you have.
Professional Japanese sword polishing (togishi) costs $2,000-$5,000 for a katana-length blade and takes months. It permanently removes steel. If your blade is a showato, polishing it is a waste of money since the blade has no grain or authentic hamon to reveal. You'll spend $3,000 to discover you have a $300 blade.
If your blade is a gendaito, polishing may or may not be worth it depending on the smith, current condition, and your goals. A gendaito by a significant wartime smith in worn but honest condition might actually be worth more to collectors than a freshly polished blade by an unknown maker.
Our advice: get the blade identified first. If it's a gendaito, submit it to NBTHK before deciding on a polish. The certification result will tell you if the investment makes sense.
Ready to explore authenticated nihonto?
Every sword in our collection has been examined, identified, and documented by our team in Tokyo. No showato. No guesswork. Browse our authentic katana collection to see what properly identified and certified nihonto look like.
Frequently Asked Questions
Is a showato worth anything?
Showato typically sell for $150-$800 depending on the condition of the blade and fittings. The gunto mountings often carry more value than the blade itself. Collectors of WW2 militaria buy them for historical interest, not as nihonto.
Will NBTHK certify a showato?
No. NBTHK only certifies traditionally forged blades. A showato will be rejected at shinsa because it was not made using tamahagane and traditional methods. Only gendaito can receive NBTHK papers.
Can a gunto contain a traditionally forged blade?
Yes. Many gunto contain gendaito blades by licensed wartime smiths. Some even contain older antique blades remounted in military fittings. Never judge a blade by its mountings.
How can I tell if my WW2 sword has a real hamon?
Hold the blade under a single bare incandescent bulb and tilt slowly. A real hamon shows crystalline activity (sparkling nie or misty nioi) with depth and variation. A fake hamon from acid etching looks flat, uniform, and sits on the surface.
Should I polish my grandfather's WW2 Japanese sword?
Not before identifying it. Polishing costs $2,000-$5,000 and only makes sense for traditionally forged blades. Polishing a showato wastes money. Get identification first, then decide.
What does the star stamp on a WW2 Japanese sword mean?
Star stamps are arsenal inspection marks from Seki or Toyokawa arsenals. The stamp alone does not tell you if the blade is showato or gendaito. Both types carry the same marks.
Key Takeaways
- Showato are machine-made wartime blades worth $150-$800. Gendaito are traditionally forged blades worth $2,000-$15,000+.
- The hamon is the primary identifier: real crystalline temper line vs. flat acid-etched line.
- Arsenal stamps and star marks do not indicate blade type.
- Get identification before polishing, selling, or making any decisions about your sword.
Related reading: Nihonto periods and budget guide | Gendaito collector's guide | NBTHK certificates explained