# Go Clock Duo: Byoyomi Timer — Baduk & Weiqi, voice countdown

> Baduk & Weiqi, voice countdown (iPhone/iPad app by Vincent Grellert.)

- Source: https://appshunter.io/ios/app/go-clock-duo-byoyomi-timer/id6795444077 (this page in markdown: same URL + `.md`)
- Developer: [Vincent Grellert](https://appshunter.io/developer/1886984960)
- Category: Utilities, Sports
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 26.0 · 14 MB
- Languages: American English, Czech, Dutch, French (France), German (Germany), Italian, Japanese, Korean, Polish, Brazilian Portuguese and 7 more
- Released: 2026-08-30
- Data updated: 2026-11-10

## What is Go Clock Duo?

The Go clock that speaks byo-yomi.
Digits large enough to read across a goban, two halves facing opposite directions, and tap zones you can hit without looking down. Byoyomi Timer turns your iPhone or iPad into the clock your club has always needed.
TIME SYSTEMS
• Japanese byo-yomi — main time plus numbered periods that reset in full with every completed move
• Canadian overtime — stone-based blocks such as 25 stones in 10 minutes, with a tappable stone counter
• Fischer bonus time — with optional cap, the current AGA standard
• Ing overtime — three purchasable periods, two penalty points each
• NHK format — 30 seconds a move backed by ten one-minute reserves
• Progressive overtime — the stone quota grows with each block
• Sudden death — a plain absolute limit
PRESETS FOR EVERY OCCASION
Blitz, quick game, club standard, tournament, tournament Canadian, AGA bonus time, NHK style, professional game, title match and Ing official. Edit any of them, or build and name your own.
A VOICE THAT COUNTS FOR YOU
The last ten seconds of every period are announced aloud, so you can keep your eyes on the board. Available in English, German, Japanese, Korean and Mandarin — chosen independently of the interface language. Prefer beeps, or silence? Both are one tap away.
PASS BUTTONS
Two consecutive passes stop the clock, exactly as the game does.
TEACHING GAMES AND HANDICAPS
Both clocks are fully independent. Different systems, different times, different period counts on each side — a teacher can play three minutes against a student's forty.
FOR REFEREES
Time, periods and stones can all be corrected mid-game without restarting.
WORKS ANYWHERE
Fully offline, even in airplane mode. Runs on the Lock Screen as a Live Activity. No account, no ads, no tracking. Your settings and history stay on your device.
ALSO AT HOME WITH
Shogi, chess, Xiangqi, Gomoku and any other two-player board game — byo-yomi is the Shogi standard, and Fischer and sudden death come from chess.
FREE AND PRO
The core clock — byo-yomi, Canadian, Fischer, sudden death and per-move play — stays free, without ads and without a time limit. Pro adds custom time systems, tournament presets, independent clocks for teaching games, fifteen further colour themes, sound packs, landscape mode, saved setups and game history. Available monthly, yearly, or as a one-time lifetime purchase.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://byoyomitimer.com/privacy/

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Pro Monthly | $0.99 | per month |
| Pro Yearly | $8.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Byoyomi Timer Pro | $24.99 | one-time |


## Is Go Clock Duo safe?

Not enough ratings yet to assess Go Clock Duo.

## Is Go Clock Duo legit?

Go Clock Duo: Byoyomi Timer appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Go Clock Duo is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 2 releases)

### 1.1 — 2026-11-06

New in version 1.1
• iPhone Duo: partly folded, the clock splits exactly at the fold, and an animation follows the hinge as you open or close it. With Pro, standing on a table with one half raised, it becomes a tournament clock: both times on the raised half, large tap areas on the flat one.
• Stop button: ends a running game right next to Pause and asks first once moves have been played.
• Game saved: after a finished game, a card sums it up with the time per move and the number of moves.
• Fixes: games that ran out while the app was closed now appear in the game history, and the time statistics count only the time that actually ran on the clock.

### 1.0 — 2026-08-31

No release notes.

## Apps similar to Go Clock Duo

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Go Baduk Weiqi Timer](https://appshunter.io/ios/app/go-baduk-weiqi-timer/id6790043280) | — | Free | Utilities |
| [Baduk Timer - AI Auto Score](https://appshunter.io/ios/app/baduk-timer-ai-auto-score/id6759492649) | — | Free | Utilities |
| [Go Time - Clock for Playing Go](https://appshunter.io/ios/app/go-time-clock-for-playing-go/id6813336069) | — | Free | Utilities |
| [Radio Pantelleria](https://appshunter.io/ios/app/radio-pantelleria/id6756185061) | — | Free | Utilities |
| [Swatch Time](https://appshunter.io/ios/app/swatch-time/id6760792721) | — | Free | Utilities |
| [ChessManager: Easy Tournaments](https://appshunter.io/ios/app/chessmanager-easy-tournaments/id6786874099) | — | Free | Utilities |

## More apps by Vincent Grellert

- [Grocery List by Voice – Pauly](https://appshunter.io/ios/app/grocery-list-by-voice-pauly/id6770338186)
- [Chess Clock Duo: Blitz Timer](https://appshunter.io/ios/app/chess-clock-duo-blitz-timer/id6792531599)

All apps by Vincent Grellert: https://appshunter.io/developer/1886984960

## Related topics

[goclock](https://appshunter.io/ios/topics/goclock) · [go baduk weiqi timer](https://appshunter.io/ios/topics/go-baduk-weiqi-timer)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-10.*