Koyomado
A simple calendar designed to sit on the Windows desktop like a compact widget.
- Status
- Stable Release
- Version
- 1.1.4
- Updated
- October 29, 2026
- Platforms
- Windows 10 / 11 (64-bit)
- Languages
- Japanese
- License
- Apache-2.0
Watch Koyomado
Introduction (about 1 minute)
Today and what comes next, in one window. A quick look at the monthly calendar, the next seven days, themes, optional Google Calendar integration, reminders and backups. The video is in Japanese.
Watch the introduction on YouTube
How-to guide (about 13 minutes, version 1.1.4)
Learn event creation and editing, recurring events, reminders and alarms, display settings, Google setup, data folders, ZIP backup and restore, automatic backups, and startup reload. Use YouTube chapters to find a task. Japanese on-screen instructions with music and sound effects; no voice narration.
Watch the guide on YouTube · Startup reload (11:56)
Calendar events are explanatory samples. If Google Cloud screens or requirements change, consult Google’s current guidance and the user manual. Music and production credits appear at the end of each video and in its YouTube description.
Updates in 1.1.4
If Google Drive or a network drive is not ready at Windows startup, the startup error screen automatically retries loading at 10-second intervals, up to three times. A successful load returns to the calendar without restarting the app. After automatic retries stop, choose 「再読み込み」 to try again manually. Retries pause during data-folder changes and never overwrite the original calendar with empty data. Calendar format v5 and ZIP format v1 are unchanged. Japanese and English manuals now include illustrated reload instructions.
What it does
Koyomado is a Windows calendar that stays on your desktop while you review your schedule. Its focused interface brings together a monthly calendar, upcoming events, recurring schedules, anniversaries, multi-day events, and notifications.
Google Calendar integration is optional. You can keep using Koyomado entirely with local data if you prefer.
Getting started
For everyday use, the Microsoft Store edition is recommended for Store-managed updates and Microsoft’s distribution signature. A portable ZIP remains available when you need to carry Koyomado between folders or devices. See the user manual for illustrated steps, including optional Google Calendar setup.
Updates in 1.1.3
Choose 「操作説明書を開く」 at the top of Settings to open the bundled PDF in Windows’ default viewer, without a network connection or Google sign-in. The Japanese cover contact link is now centered. Calendar and ZIP formats are unchanged.
Fixes in 1.1.2
Fixed ZIP backup failures caused by duplicate event IDs after disconnecting and reconnecting Google. Existing collisions are repaired by assigning unique internal IDs only after preserving and verifying the original file. No events are deleted or merged; deletion history and remote Google event IDs are retained. Reconnection also avoids creating new ID collisions.
Update both source and destination editions to 1.1.2 or later. Keep the pre-repair original private in its source folder: it can include credentials and is excluded from normal backup ZIPs.
Fixes in 1.1.1
Fixed ZIP backup rejection when active events and deletion history share an ID. IDs and all history records are retained. Results now appear beside the relevant controls. The Google networking library is also updated to its patched release.
Update both source and destination editions to 1.1.1 or later before migrating. Old 1.1.0 rejects ZIPs with shared deletion-history IDs. Retain the original calendar and ZIP.
Data protection in 1.1.0
- The Store edition can also select writable Google Drive or other local folders. Wait for the Drive client’s synchronization to finish.
- Save events, deleted-event records, appearance and sounds as a calendar ZIP; restore to an empty folder. OAuth clients and login tokens are excluded. ZIPs are not encrypted.
- Create daily, weekly or monthly backups while the app runs, retaining 1-100 generations. Only older ZIPs belonging to this configuration are pruned after a new ZIP is saved and verified.
- Concurrent startup from a shared folder is supported. Use 1.1.0 or later on every PC, wait for synchronization, and avoid simultaneous edits to the same event. Remote changes not yet synchronized cannot be detected or locked. Keep independent backups.
Data and safety
Local-only use does not send your events outside the computer. Network synchronization occurs only after you enable Google Calendar integration and choose an account. The source code is available under the Apache License 2.0.
About this build
Version 1.1.0 adds selectable data folders, ZIP backup and restore, automatic backups, and protection for shared data. The executable inside the current portable ZIP is Authenticode-signed with a Y-TEC self-signed certificate and includes an RFC 3161 timestamp. Because this is a self-signed certificate, Windows SmartScreen or security software may still display a warning.
Both manuals are available here, together with SHA-256 checksums, and a public certificate.
Microsoft Store version 1.1.4 passed certification and became publicly available on October 29, 2026. Portable 1.1.4 and Japanese/English manuals are also available here. Version 1.1.4 has been submitted to Vector and is awaiting publication (October 29, 2026). Use the Microsoft Store or portable edition for 1.1.4; check Vector for its current version. The new features require 1.1.0 or later. After updating both editions to 1.1.2 or later, export a calendar ZIP and restore it into an empty folder to migrate in either direction. The source is retained. Reconfigure Google on the destination; the first sync receives and reconciles events before normal uploads resume.
Republication
On September 29, 2026, the source, distribution files, third-party licenses, and manuals were reviewed and republished without carrying over old Git history, executables, or ZIPs. The portable executable was freshly built and signed, and the Japanese and English guides were newly generated. Application behavior, version 1.0.0, and the data format are unchanged. No Microsoft Store resubmission or Store-edition change was made.
Technologies
- Tauri 2
- React
- TypeScript
- Rust
Screenshots
Release history
Store and portable 1.1.4, manuals and two Japanese videos are available. Vector 1.1.4 has been submitted and is awaiting publication.
Fixed ZIP failures from duplicate event IDs after Google reconnection. Originals and all events are retained. Portable release and guides published; Store/Vector updates submitted.
Fixed ZIP backup validation and feedback, preserved history and patched networking. Portable 1.1.1 and guides are available; Store and Vector updates submitted.
Added data folders, ZIP backup/restore, automatic backup retention and shared-data protection. Store 1.1.0, portable build and bilingual guides are live; Vector is pending.
Koyomado 1.0.0 passed Microsoft Store certification and is now officially available, with the Store edition recommended for everyday use.
Published the first stable release with a self-signed portable build and SHA-256 checksums, and submitted the Microsoft Store build for certification.
Added notification presets, improved Google reminder syncing, and fixed the Add Event button overflowing near the minimum window width.
Added per-event notifications, notification sounds, display scaling, a default Google Calendar destination, and an expanded user manual.
Updated OAuth and Google API networking dependencies and prevented HTTP redirects for a focused security update.
Added multi-day and recurring events, optional two-way Google Calendar sync, display-location settings, and open-source release preparation.
Saved window position and size for each monitor setup and strengthened recovery when a saved window would appear off-screen.
Fixed Today after the date changes, added right-click deletion, and made empty dates open the event editor directly.
Bundled an illustrated PDF manual covering first launch, event controls, data migration, and troubleshooting.
First public version with the monthly calendar, event editing, annual occasions, themes, tray controls, and portable storage.