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docs/develop/blockchain/shards.mdx

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+# TON Shards
+
+Sharding is a mechanism in TON blockchain which allows to process a large number of transactions. The main idea of sharding in TON is that when account A sends a message to account B and account C sends a message to account D both of these operations can be performed asynchronously.
+
+By default in the Basechain (`workchain=0`) there is only one shard with a shard number `0x8000000000000000` (or `1000000000000000000000000000000000000000000000000000000000000000` in binary representation). The masterchain (`workchain=-1`) always has one and only one shard.
+
+## Splitting
+
+Each shard is responsible for some subset of accounts with some common binary prefix. This prefix appears in shard id which presented by a 64-bit integer and has the following structure: `<binary prefix>100000...`. For example, shard with id `1011100000...` contains all accounts started with prefix `1011`.
+
+When number of transactions in some shard growth, it splits into two shards. New shards obtaining the following ids: `<parent prefix>01000...` and `<parent prefix>11000...` and responsible for accounts starting with `<parent prefix>0` and `<parent prefix>1` correspondingly. The seqnos of blocks in shards goes continuously starting from parent last seqno plus 1. After split shards go independently and may have different seqnos.
+
+Masterchain block contains information about shards in its header. After the block of shard appears in masterchain header it may be considered as finished (it cannot be rolled back).
+
+Example:
+* Masterchain block `seqno=34607821` has 2 shards: `(0,4000000000000000,40485798)` and `(0,c000000000000000,40485843)` (https://toncenter.com/api/v2/shards?seqno=34607821).
+* Shard `shard=4000000000000000` was splitted into `shard=2000000000000000` and `shard=6000000000000000` and masterchain block `seqno=34607822` already has 3 shards: `(0,2000000000000000,40485799)` and `(0,6000000000000000,40485799)`. Note, that both new shards has the same seqnos but different shard IDs (https://toncenter.com/api/v2/shards?seqno=34607822).
+* New shards go independently and after 100 masterchain blocks (in masterchain block `seqno=34607921`) one shard has last block `(0,2000000000000000,40485901)` and another one has `(0,6000000000000000,40485897)` (https://toncenter.com/api/v2/shards?seqno=34607921).
+
+## Merging
+When shards load goes down they can merge back as follow:
+* Two shards can merge if they have common parent and, therefore, their shard ids are `<parent prefix>010...` and `<parent prefix110...`. Merged shard will have shard id `<parent prefix>10...` (for example `10010...` + `10110...` = `1010...`). The first block of merged shard will have `seqno=max(seqno1, seqno2) + 1`.
+
+Example:
+* In masterchain block `seqno=34626306` two of five shards with last blocks `(0,a000000000000000,40492030)` and `(0,e000000000000000,40492216)` merged into one with block `(0,c000000000000000,40492217)` (https://toncenter.com/api/v2/shards?seqno=34626306 and https://toncenter.com/api/v2/shards?seqno=34626307).

sidebars.js

@@ -554,8 +554,8 @@ const sidebars = {
           type: 'category',
           label: 'Blockchain Fundamentals',
           items: [
-
-            'develop/blockchain/sharding-lifecycle',
+              'develop/blockchain/shards',
+              'develop/blockchain/sharding-lifecycle',
           ],
         },
     {