Tech Bureau, Corp. logo

Tech Bureau, Corp.

Tech Bureau, Corp. is a Japanese blockchain technology company. It develops the mijin private-blockchain solution and operates DocuTracker, a blockchain-backed digital archive certification SaaS; it also operated the COMSA NFT marketplace, whose service closure was announced and reported in 2025–2026.
Osaka, JP

COMSA


Project Links


Description

COMSA operated an NFT marketplace and provided related post-closure services, including COMSA Bundle NFT transfers, wallet mnemonic-backup information, Japanese-yen withdrawal and NFT transaction-history access, and a COMSA NFT blockchain explorer. The site states that the marketplace ended service on January 31, 2026; its Token Sale Dashboard ended on November 30, 2022.

Category: NFT Marketplace

Mijin


Project Links


Description

mijin is a private blockchain platform for token-economy applications. It provides distributed ledger functionality, native multisignature support, multi-asset management, and APIs for issuing, circulating, and accounting for assets, with deployment and service options including mijin BaaS and mijin BOD.

Category: L1

DocuTracker


Project Links


Description

DocuTracker integrates with Google Drive, Microsoft OneDrive, Dropbox, and Box to automatically record file hashes, timestamps, and operation logs for stored documents on a dedicated private blockchain using mijin. It supports electronic-record retention use cases, guest access for tax officials or external supervisory bodies, and an optional monitoring feature that notifies customers when archived files change.

Category: Decentralized File Storage