---
title: Open Book
description: "Play 0x3A, server → client."
---

`play` · `0x3A` · **clientbound** (server → client)

Tells the client to open the book screen for the written book held in `hand` (main hand or off hand). The server sends it when the player uses a written book. The client reads the book contents from the item stack in that hand.

Sent by the server, read by the client. Listen for it with `client.on("OpenBook", (data) => …)` on the receiving side.

## Fields

| Field | Type | Notes |
|---|---|---|
| `hand` | VarInt |  |

## Send it

```ts
await client.sendPacket("OpenBook", {
  hand: /* VarInt */,
});
```

Field aliases listed under Notes are accepted as alternative keys when writing.

Source: [`src/Core/Versions/776/Packets/play/clientbound/OpenBook.ts`](https://github.com/GDLev/mc-protocol/blob/master/src/Core/Versions/776/Packets/play/clientbound/OpenBook.ts)