---
title: "Grindstone Pentahydrate Drop Rates (JP server)"
description: "Grindstone Pentahydrate drop rates on the JP server: 4-8 4.71% (6,514 samples), 7-17 3.92% (1,838), 12-8 2.78% (432); 8 stages in total. Updated 2026-10-23. Crowdsourced Arknights drop data by Penguin Statistics."
lang: en
server: JP
item_id: "30094"
as_of: 2026-10-23T14:30:52Z
time_zone: UTC+9
rows: 8
rows_total: 8
canonical: "https://penguin-stats.io/en/result/jp/item/30094"
api: "https://penguin-stats.io/PenguinStats/api/v2/result/matrix?server=JP&itemFilter=30094&show_closed_zones=true"
license: CC BY-NC 4.0
license_url: https://creativecommons.org/licenses/by-nc/4.0/
attribution: "Data: Penguin Statistics (penguin-stats.io), CC BY-NC 4.0"
---

# Grindstone Pentahydrate Drop Rates (JP server)

Server: [CN server](https://penguin-stats.io/en/result/cn/item/30094.md) · [US server](https://penguin-stats.io/en/result/us/item/30094.md) · **JP server** · [KR server](https://penguin-stats.io/en/result/kr/item/30094.md)

Drops of Grindstone Pentahydrate by stage on the JP server, by percentage, highest first: 8 of 8 stages

| Stage | ID | Loots | Samples | Percentage | Sanity Required Per Item | Sanity | Time Range |
| --- | --- | ---: | ---: | ---: | ---: | ---: | --- |
| [13-21](https://penguin-stats.io/en/result/jp/stage/main_13/main_13-19.md) Episode 13 (Standard) | `main_13-19` | 3 | 30 | 10.00% | 240.00 | 24 | 2024-03-19 until now |
| [14-5](https://penguin-stats.io/en/result/jp/stage/main_14/main_14-04.md) Episode 14 (Standard) | `main_14-04` | 4 | 67 | 5.97% | 351.76 | 21 | 2024-11-14 until now |
| [4-8](https://penguin-stats.io/en/result/jp/stage/main_4/main_04-08.md) Episode 4 | `main_04-08` | 307 | 6514 | 4.71% | 445.58 | 21 | 2020-01-16 until now |
| [7-17](https://penguin-stats.io/en/result/jp/stage/main_7/main_07-15.md) Episode 7 | `main_07-15` | 72 | 1838 | 3.92% | 536.12 | 21 | 2020-12-30 until now |
| [TW-8](https://penguin-stats.io/en/result/jp/stage/permanent_sidestory_4_zone1/act11d0_08_perm.md) Twilight of Wolumonde - Side Story | `act11d0_08_perm` | 6 | 180 | 3.33% | 540.05 | 18 | 2021-12-31 until now |
| [12-8](https://penguin-stats.io/en/result/jp/stage/main_12_tough/tough_12-07.md) Episode 12 (Tough) | `tough_12-07` | 12 | 432 | 2.78% | 755.94 | 21 | 2023-10-24 until now |
| [BI-8](https://penguin-stats.io/en/result/jp/stage/permanent_sidestory_11_zone1/act14side_08_perm.md) Break The Ice - Side Story | `act14side_08_perm` | 1 | 59 | 1.70% | 1061.95 | 18 | 2023-06-27 until now |
| [12-8](https://penguin-stats.io/en/result/jp/stage/main_12/main_12-07.md) Episode 12 (Standard) | `main_12-07` | 3 | 192 | 1.56% | 1343.57 | 21 | 2023-10-24 until now |

Samples: runs of the stage reported in the time range. Loots: total number of the item dropped in those runs. Percentage = Loots ÷ Samples, the expected number dropped per run, which can exceed 100%. Sanity Required Per Item = Sanity ÷ Percentage. Time Range: since the drop table of the stage last changed.

Updated 2026-10-23 23:30 (UTC+9). [Full data (JSON)](https://penguin-stats.io/PenguinStats/api/v2/result/matrix?server=JP&itemFilter=30094&show_closed_zones=true). License: [CC BY-NC 4.0](https://creativecommons.org/licenses/by-nc/4.0/)

## Related Items

- [Grindstone](https://penguin-stats.io/en/result/jp/item/30093.md) `30093`