{
  "schemaVersion": 1,
  "canonicalUrl": "https://zufu.whiskey.works/objects/gassan-tanto/",
  "recordUrl": "https://zufu.whiskey.works/objects/gassan-tanto/record.json",
  "accession": "NA 2026.011",
  "title": "Tantō Signed Gassan",
  "japaneseTitle": "短刀 · 月山銘",
  "classification": {
    "category": "nihonto",
    "form": "tanto",
    "presentation": [
      "koshirae"
    ]
  },
  "period": "Period unrecorded · not established",
  "summary": "An unpapered 19.6 cm hira-zukuri tantō in a black-lacquer aikuchi-style koshirae, carrying a worn short mei read in the source as Gassan; a regular undulating grain is visible along the blade.",
  "attribution": {
    "label": "Gassan · mei as read",
    "japanese": "月山（銘）",
    "qualifier": "Short worn signature; the source reads it as Gassan and the second character supports that, but the remaining characters are not resolved and no generation or maker is asserted"
  },
  "highlights": [
    {
      "label": "Nagasa",
      "value": "19.6 cm"
    },
    {
      "label": "Sori",
      "value": "0.0 cm"
    },
    {
      "label": "Mei",
      "value": "月山 · partly legible"
    }
  ],
  "revisedOn": "2026-08-20",
  "revisions": [
    {
      "date": "2026-08-20",
      "note": "Catalogue record established from the ended listing and its 18 gallery photographs; the worn mei and the visible longitudinal grain are both recorded as observations."
    }
  ],
  "hero": {
    "image": "https://zufu.whiskey.works/media/na-2026-011/01.jpg",
    "alt": "Tantō drawn beside its black-lacquered saya with the cord tied around it"
  },
  "sections": [
    {
      "title": "Object record",
      "facts": [
        {
          "label": "Item",
          "value": "Tantō (短刀) in black-lacquer koshirae"
        },
        {
          "label": "Mei",
          "value": "Short, worn · read in the source as Gassan\n月山（銘・磨滅）"
        },
        {
          "label": "Nagasa",
          "value": "19.6 cm"
        },
        {
          "label": "Sori",
          "value": "0.0 cm · muzori"
        },
        {
          "label": "Width",
          "value": "Motohaba 2.5 cm"
        },
        {
          "label": "Kasane",
          "value": "Motogasane 0.4 cm"
        },
        {
          "label": "Construction",
          "value": "Hira-zukuri · no shinogi or yokote"
        },
        {
          "label": "Mekugi-ana",
          "value": "One · both nakago faces photographed"
        },
        {
          "label": "Period",
          "value": "Unrecorded · no appraisal paper supplied"
        }
      ],
      "notes": [
        {
          "lead": "Attribution boundary.",
          "body": "The source description gives the signature only in romaji, as “Gassan Masa”, without kanji. In the photographs the inscription is a short column of shallow characters below the mekugi-ana, most of it worn past reading; one character reads convincingly as 山. That is consistent with 月山 but does not confirm it, and the character transcribed as “Masa” is not resolvable at all. No smith, generation, or period is asserted here."
        },
        {
          "lead": "Corroborating observation.",
          "body": "Separately from the inscription, the blade shows a regular undulating grain running the length of both faces — visible even through a spent polish. A wavy grain of that kind (ayasugi-hada) is the Gassan school's most-cited diagnostic, which makes this an independent line of evidence rather than a restatement of the signature. It is recorded here as a surface observation only: confirming it as ayasugi, and distinguishing it from polishing artefact, requires the blade in hand under proper light."
        }
      ]
    },
    {
      "title": "Condition record",
      "facts": [
        {
          "label": "Photographs",
          "value": "Eighteen archival photographs · no video"
        },
        {
          "label": "Documents",
          "value": "No registration card, NBTHK/NTHK paper, or other certificate shown"
        }
      ],
      "notes": [
        {
          "lead": "Visible record.",
          "body": "The polish is spent: the blade reads dark grey over most of its area with brighter bands where light catches the flat, and small reddish freckles scattered near the edge. The tang is dark and evenly corroded. Nothing here classifies a defect."
        }
      ]
    }
  ],
  "plates": [
    {
      "number": "IV.1",
      "group": "IV",
      "groupTitle": "Koshirae & Ensemble",
      "title": "Ensemble, drawn",
      "japanese": "拵・全体",
      "caption": "The blade laid beside its mounting. The saya is plain glossy black lacquer with a black cord tied around it through a low kurikata; the tsuka is wrapped in a fine cream-and-black lozenge pattern over white same and closed with a black horn kashira.",
      "alt": "Tantō blade drawn and laid beside its black-lacquered saya with cord",
      "image": "https://zufu.whiskey.works/media/na-2026-011/01.jpg",
      "redacted": false
    },
    {
      "number": "IV.2",
      "group": "IV",
      "groupTitle": "Koshirae & Ensemble",
      "title": "Koshirae, housed",
      "japanese": "拵・全体",
      "caption": "The mounting closed. The koiguchi meets the fuchi without a visible guard standing proud of the profile, giving the aikuchi-style line of a companion dagger mounting.",
      "alt": "Complete koshirae with the blade housed and the cord tied",
      "image": "https://zufu.whiskey.works/media/na-2026-011/02.jpg",
      "redacted": false
    },
    {
      "number": "IV.3",
      "group": "IV",
      "groupTitle": "Koshirae & Ensemble",
      "title": "Blade mounted",
      "japanese": "拵・全体",
      "caption": "The blade assembled in its hilt, showing the gilt habaki, the small dark tsuba seated tight against the fuchi, and the proportion of a 19.6 cm blade to its mounting.",
      "alt": "The blade assembled in its tsuka with habaki and small tsuba in place",
      "image": "https://zufu.whiskey.works/media/na-2026-011/03.jpg",
      "redacted": false
    },
    {
      "number": "II.1",
      "group": "II",
      "groupTitle": "Sugata & Nakago",
      "title": "Full sugata · mei face",
      "japanese": "姿・茎",
      "caption": "Full length on the face carrying the inscription. Nagasa 19.6 cm with no sori at all and 0.4 cm kasane (measurements per the source description). The section is hira-zukuri throughout, and the tang tapers to a rounded end.",
      "alt": "Full blade, mei face, tip at upper left and tang at lower right",
      "image": "https://zufu.whiskey.works/media/na-2026-011/04.jpg",
      "redacted": false
    },
    {
      "number": "II.2",
      "group": "II",
      "groupTitle": "Sugata & Nakago",
      "title": "Full sugata · reverse",
      "japanese": "姿・茎",
      "caption": "Full length on the reverse, which carries no inscription. The undulating longitudinal figure in the steel is visible here at full-blade scale as a series of soft repeating bands.",
      "alt": "Full blade, reverse face, tip at upper right and tang at lower left",
      "image": "https://zufu.whiskey.works/media/na-2026-011/05.jpg",
      "redacted": false
    },
    {
      "number": "II.3",
      "group": "II",
      "groupTitle": "Sugata & Nakago",
      "title": "Nakago · mei",
      "japanese": "姿・茎",
      "caption": "The tang with one mekugi-ana and a short column of characters cut below it. The strokes are shallow and largely eaten by corrosion; one character reads convincingly as 山, and the others are not recoverable at this resolution. The source transcribes the whole as “Gassan Masa” in romaji only.",
      "alt": "Close view of the tang showing one mekugi-ana and a short worn inscription",
      "image": "https://zufu.whiskey.works/media/na-2026-011/06.jpg",
      "redacted": false
    },
    {
      "number": "II.4",
      "group": "II",
      "groupTitle": "Sugata & Nakago",
      "title": "Nakago-jiri",
      "japanese": "姿・茎",
      "caption": "The tang end, rounded in a kurijiri-like curve. Patina is dark and mottled with green-black and rust tones; file marks are not resolved.",
      "alt": "The rounded end of the tang with heavy dark patina",
      "image": "https://zufu.whiskey.works/media/na-2026-011/07.jpg",
      "redacted": false
    },
    {
      "number": "II.5",
      "group": "II",
      "groupTitle": "Sugata & Nakago",
      "title": "Mune & machi",
      "japanese": "姿・茎",
      "caption": "The back edge photographed along its length, showing the bright polished mune giving way to the dark tang at a clean step.",
      "alt": "The back edge at the transition from blade to tang",
      "image": "https://zufu.whiskey.works/media/na-2026-011/08.jpg",
      "redacted": false
    },
    {
      "number": "II.6",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Surface · undulating grain",
      "japanese": "地刃",
      "caption": "The clearest record of the blade's figure: a repeating wavy pattern runs lengthwise across the whole width, regular in period and consistent from one face to the other. It is described here as observed. Whether it is ayasugi-hada in the steel or an artefact of an old polish is left for examination in hand.",
      "alt": "Mid-blade surface showing a repeating wavy longitudinal figure in the steel",
      "image": "https://zufu.whiskey.works/media/na-2026-011/13.jpg",
      "redacted": false
    },
    {
      "number": "II.7",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Surface · above the machi",
      "japanese": "地刃",
      "caption": "Just above the machi. Small white deposits sit on the flat alongside dark specks and short scratches; the wavy figure continues under them.",
      "alt": "Blade surface near the machi with white deposits and dark specks",
      "image": "https://zufu.whiskey.works/media/na-2026-011/14.jpg",
      "redacted": false
    },
    {
      "number": "II.8",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Surface · bright reflection",
      "japanese": "地刃",
      "caption": "The same region under a stronger reflection, which flattens the figure and shows the machi notch at the frame edge. Retained as part of the complete gallery record.",
      "alt": "Blade surface under bright reflection with the machi notch at the frame edge",
      "image": "https://zufu.whiskey.works/media/na-2026-011/16.jpg",
      "redacted": false
    },
    {
      "number": "II.9",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Surface · toward the point",
      "japanese": "地刃",
      "caption": "Toward the point, where a broad bright band crosses the flat and the darker ground resumes beyond it. Fine pitting is visible along the lower edge of the frame.",
      "alt": "Blade surface toward the point with a broad bright band",
      "image": "https://zufu.whiskey.works/media/na-2026-011/17.jpg",
      "redacted": false
    },
    {
      "number": "II.10",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Point · first face",
      "japanese": "地刃",
      "caption": "The point on the first face. With no yokote on a hira-zukuri blade the surface runs uninterrupted into the tip; the fukura is full and the outline undamaged.",
      "alt": "Point section, dark, with a full curved edge profile",
      "image": "https://zufu.whiskey.works/media/na-2026-011/15.jpg",
      "redacted": false
    },
    {
      "number": "II.11",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Point · second face",
      "japanese": "地刃",
      "caption": "The point on the second face, where a bright band follows the edge into the tip and a small rust patch sits at the extreme point.",
      "alt": "Point section, second face, with a bright band along the edge",
      "image": "https://zufu.whiskey.works/media/na-2026-011/18.jpg",
      "redacted": false
    },
    {
      "number": "II.12",
      "group": "II",
      "groupTitle": "Ji & Ha",
      "title": "Point, near-edge-on",
      "japanese": "地刃",
      "caption": "A near-edge-on record of the same point, showing how thin the section runs out at the tip on a 0.4 cm kasane blade.",
      "alt": "Near-edge-on view of the steel narrowing to the point",
      "image": "https://zufu.whiskey.works/media/na-2026-011/09.jpg",
      "redacted": false
    },
    {
      "number": "III.1",
      "group": "III",
      "groupTitle": "Koshirae Fittings",
      "title": "Habaki · first face",
      "japanese": "拵金具",
      "caption": "The habaki off the blade: one piece of gilt copper alloy, plain, with a stepped upper edge and lengthwise working marks across the face.",
      "alt": "Gilt one-piece habaki, first face",
      "image": "https://zufu.whiskey.works/media/na-2026-011/10.jpg",
      "redacted": false
    },
    {
      "number": "III.2",
      "group": "III",
      "groupTitle": "Koshirae Fittings",
      "title": "Habaki · second face",
      "japanese": "拵金具",
      "caption": "The reverse of the habaki, showing the same plain gilt surface and the seating step that bears against the machi.",
      "alt": "Gilt one-piece habaki, second face",
      "image": "https://zufu.whiskey.works/media/na-2026-011/11.jpg",
      "redacted": false
    },
    {
      "number": "III.3",
      "group": "III",
      "groupTitle": "Koshirae Fittings",
      "title": "Tsuba, seppa & tsuka",
      "japanese": "拵金具",
      "caption": "The dismounted fittings: a small dark iron tsuba of lobed outline with three small gold accents around the seppa-dai and traces of surface carving, a plain oval copper seppa, and the tsuka wrapped in a tight cream-and-black lozenge pattern over white same. Dark menuki with gold highlights sit under the wrap, and the black fuchi and kashira carry small gold inlaid details.",
      "alt": "Small dark iron tsuba with gold accents, a copper seppa and the wrapped tsuka",
      "image": "https://zufu.whiskey.works/media/na-2026-011/12.jpg",
      "redacted": false
    }
  ],
  "rights": {
    "catalogue": "© 2026 whiskey.works",
    "photographs": "Courtesy of GN-1-Japan, used with permission. No downstream reproduction permission is granted."
  }
}