Katana or Shin Gunto for an Imperial Japanese Army Officer made by Seki Kanesada. The structure of the Koshirae and the blade indicate that this is a Type 98 model that retains all its original parts.

This model with a wooden scabbard and leather sheath was used in the middle and end of World War II for two reasons: a) due to the lack of materials such as metal or aluminium and b) because it was more useful on the battlefield (less weight and less noise).

Original Japanese Katana from World War II.

The Koshirae or structure
The scabbard (鞘 Saya) is made of lacquered wood with a leather sheath. It has the upper anchor (帯執 Obi-tori) to attach it to the belt.
The format of the metal guard (鍔 Tsuba) is the characteristic solid one from the middle of the war. It contains 5 Seppa, three upper and two lower.

The braiding (柄糸Tsukaito) of the hilt (柄Tsuka) is of the Morohinerimaki type. The ray skin (鮫Same) inside is in good condition although worn in some places. It also contains the original upper metal piece (頭Kashira) in a smooth shape. It has a Menuki (目貫) on each side with floral motifs.

The Nagasa or blade
We can highlight the following characteristics of the blade:
The overall shape of the blade is Shinogi-zukuri like most shin gunto.
The temple around the cut (刃文Hamon) is of the Sugu type (straight).
The steel pattern of the blade (地肌Jiada) is Muji type (flat or smooth)
The backcut (棟Mune) is Ihori type (single open angle)
On the tang (茎Nakago) you can read the craftsman’s signature (名Mei) and it contains a single hole.
The blade has stains, presumably from having been in contact with some material inside the scabbard. It retains its edge.

The Mei or signature
On the Nakago you can read the Mei, the name of the craftsman forger Seki Kanesada (関兼定) and the Sho stamp.