# PlainShogiBoard / Plain将棋盤 vs MentalCalculation & Abacus Pro

The clearest difference is price: PlainShogiBoard / Plain将棋盤 at Free against MentalCalculation & Abacus Pro's $0.99. PlainShogiBoard / Plain将棋盤 also leads on ads (none vs shown) and device support (6 vs 3). MentalCalculation & Abacus Pro's advantage is in-app purchases (none vs 1) and update cadence (monthly vs every 2 months).

PlainShogiBoard / Plain将棋盤 is free to download; MentalCalculation & Abacus Pro costs $0.99 up front. PlainShogiBoard / Plain将棋盤 sells 1 one-off in-app purchase. MentalCalculation & Abacus Pro asks for nothing beyond the download.

PlainShogiBoard / Plain将棋盤 ships an update every 2 months, MentalCalculation & Abacus Pro monthly. The most recent releases landed on November 3, 2026 and November 8, 2026 respectively.

## The numbers

| Metric | PlainShogiBoard / Plain将棋盤 | MentalCalculation & Abacus Pro |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Monthly** |
| Monetization | — | Paid |
| Size | 7 MB | 144 MB |
| Requires iOS | 27.0 | **12.0** |
| Devices | **iPhone, iPad, Mac, Apple TV, Apple Watch, Vision Pro** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ryo Yamashita](https://appshunter.io/developer/1347562710) | [Park Jisang](https://appshunter.io/developer/995438886) |

## What reviewers say

### PlainShogiBoard / Plain将棋盤

[App page](https://appshunter.io/ios/app/plainshogiboard-plain/id1620268476)

**Features:** Apple Watch app, SharePlay

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Hide AD | $1.99 | one-time |


### MentalCalculation & Abacus Pro

[App page](https://appshunter.io/ios/app/mentalcalculation-and-abacus-pro/id6474296462)

Engage in a fun and challenging mental calculation and abacus game. Practice with diverse questions and learn the abacus with an easy tutorial. This pro version offers an enhanced experience without frequent forced ads.

**Highlights:** Mental calculation practice, Abacus learning tutorial, Variety of practice questions, Pro version benefits, No forced ads

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is PlainShogiBoard / Plain将棋盤 free?

PlainShogiBoard / Plain将棋盤 is free to download, with in-app purchases available.

### Is MentalCalculation & Abacus Pro free?

MentalCalculation & Abacus Pro costs $0.99, with no in-app purchases.

### Do PlainShogiBoard / Plain将棋盤 or MentalCalculation & Abacus Pro have ads?

MentalCalculation & Abacus Pro shows ads; PlainShogiBoard / Plain将棋盤 does not.

### Which is updated more often, PlainShogiBoard / Plain将棋盤 or MentalCalculation & Abacus Pro?

PlainShogiBoard / Plain将棋盤 ships an update every 2 months, and MentalCalculation & Abacus Pro monthly. Most recently, PlainShogiBoard / Plain将棋盤 was updated on November 3, 2026 and MentalCalculation & Abacus Pro on November 8, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*