XRPLF · mDuo13 · Jan 26, 2018 · Jan 17, 2018 · Jan 19, 2018 · Jan 20, 2018
diff --git a/content/concept-reserves.md b/content/concept-reserves.md
@@ -25,6 +25,7 @@ Many objects in the ledger are owned by a particular address, and count toward t
 - [Held Payments (Escrow)](reference-ledger-format.html#escrow) are owned by the address that placed them.
 - [Payment Channels](tutorial-paychan.html) are owned by the address that created them.
 - [Owner directories](reference-ledger-format.html#directorynode) list all the ledger objects that contribute to an address's owner reserve. However, the owner directory itself does not count towards the reserve.
+- Checks are owned by the address that created them (the sender, not the destination). <!--{# TODO: link the concept or tutorial when one exists #}-->
 
 #### Owner Reserve Edge Cases
 

diff --git a/content/ledger-objects/accountroot.md b/content/ledger-objects/accountroot.md
@@ -0,0 +1,69 @@
+## AccountRoot
+[[Source]<br>](https://github.com/ripple/rippled/blob/5d2d88209f1732a0f8d592012094e345cbe3e675/src/ripple/protocol/impl/LedgerFormats.cpp#L27 "Source")
+
+The `AccountRoot` object type describes a single _account_ object. Example `AccountRoot` object:
+
+```json
+{
+    "Account": "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn",
+    "AccountTxnID": "0D5FB50FA65C9FE1538FD7E398FFFE9D1908DFA4576D8D7A020040686F93C77D",
+    "Balance": "148446663",
+    "Domain": "6D64756F31332E636F6D",
+    "EmailHash": "98B4375E1D753E5B91627516F6D70977",
+    "Flags": 8388608,
+    "LedgerEntryType": "AccountRoot",
+    "MessageKey": "0000000000000000000000070000000300",
+    "OwnerCount": 3,
+    "PreviousTxnID": "0D5FB50FA65C9FE1538FD7E398FFFE9D1908DFA4576D8D7A020040686F93C77D",
+    "PreviousTxnLgrSeq": 14091160,
+    "Sequence": 336,
+    "TransferRate": 1004999999,
+    "index": "13F1A95D7AAB7108D5CE7EEAF504B2894B8C674E6D68499076441C4837282BF8"
+}
+```
+
+The `AccountRoot` object has the following fields:
+
+| Field           | JSON Type | [Internal Type][] | Description |
+|-----------------|-----------|---------------|-------------|
+| `LedgerEntryType` | String | UInt16 | The value `0x0061`, mapped to the string `AccountRoot`, indicates that this object is an AccountRoot object. |
+| `Account`         | String | AccountID | The identifying address of this account, such as rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn. |
+| [`Flags`](#accountroot-flags) | Number | UInt32 | A bit-map of boolean flags enabled for this account. |
+| `Sequence`        | Number | UInt32 | The sequence number of the next valid transaction for this account. (Each account starts with Sequence = 1 and increases each time a transaction is made.) |
+| `Balance`         | String | Amount | The account's current [XRP balance in drops][XRP, in drops], represented as a string. |
+| `OwnerCount`      | Number | UInt32 | The number of objects this account owns in the ledger, which contributes to its owner reserve. |
+| `PreviousTxnID`   | String | Hash256 | The identifying hash of the transaction that most recently modified this object. |
+| `PreviousTxnLgrSeq` | Number | UInt32 | The [index of the ledger](#ledger-index) that contains the transaction that most recently modified this object. |
+| `AccountTxnID`    | String | Hash256 | (Optional) The identifying hash of the transaction most recently submitted by this account. |
+| `RegularKey`      | String | AccountID | (Optional) The address of a keypair that can be used to sign transactions for this account instead of the master key. Use a [SetRegularKey transaction][] to change this value. |
+| `EmailHash`       | String | Hash128 | (Optional) The md5 hash of an email address. Clients can use this to look up an avatar through services such as [Gravatar](https://en.gravatar.com/). |
+| `WalletLocator`   | String | Hash256 | (Optional) **DEPRECATED**. Do not use. |
+| `WalletSize`      | Number | UInt32  | (Optional) **DEPRECATED**. Do not use. |
+| `MessageKey`      | String | VariableLength  | (Optional) A public key that may be used to send encrypted messages to this account. In JSON, uses hexadecimal. No more than 33 bytes. |
+| `TickSize`        | Number | UInt8   | (Optional) How many significant digits to use for exchange rates of Offers involving currencies issued by this address. Valid values are `3` to `15`, inclusive. _(Requires the [TickSize amendment](reference-amendments.html#ticksize).)_ |
+| `TransferRate`    | Number | UInt32  | (Optional) A [transfer fee](https://ripple.com/knowledge_center/transfer-fees/) to charge other users for sending currency issued by this account to each other. |
+| `Domain`          | String | VariableLength | (Optional) A domain associated with this account. In JSON, this is the hexadecimal for the ASCII representation of the domain. |
+
+### AccountRoot Flags
+
+There are several options which can be either enabled or disabled for an account. These options can be changed with an [AccountSet transaction][]. In the ledger, flags are represented as binary values that can be combined with bitwise-or operations. The bit values for the flags in the ledger are different than the values used to enable or disable those flags in a transaction. Ledger flags have names that begin with _lsf_.
+
+AccountRoot objects can have the following flag values:
+
+| Flag Name | Hex Value | Decimal Value | Description | Corresponding [AccountSet Flag](reference-transaction-format.html#accountset-flags) |
+|-----------|-----------|---------------|-------------|-------------------------------|
+| lsfPasswordSpent | 0x00010000 | 65536 | Indicates that the account has used its free SetRegularKey transaction. | (None) |
+| lsfRequireDestTag | 0x00020000 | 131072 | Requires incoming payments to specify a Destination Tag. | asfRequireDest |
+| lsfRequireAuth | 0x00040000 | 262144 | This account must individually approve other users for those users to hold this account's issuances. | asfRequireAuth |
+| lsfDisallowXRP | 0x00080000 | 524288 | Client applications should not send XRP to this account. Not enforced by `rippled`. | asfDisallowXRP |
+| lsfDisableMaster | 0x00100000 | 1048576 | Disallows use of the master key to sign transactions for this account. | asfDisableMaster |
+| lsfNoFreeze | 0x00200000 | 2097152 | This address cannot freeze trust lines connected to it. Once enabled, cannot be disabled. | asfNoFreeze |
+| lsfGlobalFreeze | 0x00400000 | 4194304 |　All assets issued by this address are frozen. | asfGlobalFreeze |
+| lsfDefaultRipple | 0x00800000 | 8388608 | Enable [rippling](concept-noripple.html) on this addresses's trust lines by default. Required for issuing addresses; discouraged for others. | asfDefaultRipple |
+
+### AccountRoot ID Format
+
+The ID of an AccountRoot object is the [SHA-512Half](#sha512half) of the following values put together:
+
+* The Account space key (`0x0061`)
+* The AccountID of the account
diff --git a/content/ledger-objects/amendments.md b/content/ledger-objects/amendments.md
@@ -0,0 +1,56 @@
+## Amendments
+[[Source]<br>](https://github.com/ripple/rippled/blob/develop/src/ripple/protocol/impl/LedgerFormats.cpp#L110-L113 "Source")
+
+The `Amendments` object type contains a list of [Amendments](concept-amendments.html) that are currently active. Each ledger version contains **at most one** `Amendments` object.
+
+Example `Amendments` object:
+
+```json
+{
+    "Majorities": [
+        {
+            "Majority": {
+                "Amendment": "1562511F573A19AE9BD103B5D6B9E01B3B46805AEC5D3C4805C902B514399146",
+                "CloseTime": 535589001
+            }
+        }
+    ],
+    "Amendments": [
+        "42426C4D4F1009EE67080A9B7965B44656D7714D104A72F9B4369F97ABF044EE",
+        "4C97EBA926031A7CF7D7B36FDE3ED66DDA5421192D63DE53FFB46E43B9DC8373",
+        "6781F8368C4771B83E8B821D88F580202BCB4228075297B19E4FDC5233F1EFDC",
+        "740352F2412A9909880C23A559FCECEDA3BE2126FED62FC7660D628A06927F11"
+    ],
+    "Flags": 0,
+    "LedgerEntryType": "Amendments",
+    "index": "7DB0788C020F02780A673DC74757F23823FA3014C1866E72CC4CD8B226CD6EF4"
+}
+```
+
+| Name              | JSON Type | [Internal Type][] | Description |
+|-------------------|-----------|-------------------|-------------|
+| `Amendments`      | Array     | STI_VECTOR256     | _(Optional)_ Array of 256-bit [amendment IDs](concept-amendments.html#about-amendments) for all currently-enabled amendments. If omitted, there are no enabled amendments. |
+| `Majorities`      | Array     | STI_ARRAY | _(Optional)_ Array of objects describing the status of amendments that have majority support but are not yet enabled. If omitted, there are no pending amendments with majority support. |
+| `Flags`           | Number    | UInt32    | Not used. |
+| `LedgerEntryType` | String    | UInt16    |  The value `0x0066`, mapped to the string `Amendments`, indicates that this is object describes status of amendments to the XRP Ledger. |
+
+Each member of the `Majorities` field, if it is present, is an object with a one field, `Majority`, whose contents are a nested object with the following fields:
+
+| Name              | JSON Type | [Internal Type][] | Description |
+|-------------------|-----------|-------------------|-------------|
+| `Amendment`       | String    | Hash256           | The Amendment ID of the pending amendment. |
+| `CloseTime`       | Number    | UInt32            | The [`close_time` field](#header-format) of the ledger version where this amendment most recently gained a majority. |
+
+In the [amendment process](concept-amendments.html#amendment-process), a consensus of validators adds a new amendment to the `Majorities` field using an [EnableAmendment][] pseudo-transaction with the `tfGotMajority` flag when 80% or more of validators support it. If support for a pending amendment goes below 80%, an [EnableAmendment][] pseudo-transaction with the `tfLostMajority` flag removes the amendment from the `Majorities` array. If an amendment remains in the `Majorities` field for at least 2 weeks, an [EnableAmendment][] pseudo-transaction with no flags removes it from `Majorities` and permanently adds it to the `Amendments` field.
+
+**Note:** Technically, all transactions in a ledger are processed based on which amendments are enabled in the ledger version immediately before it. While applying transactions to a ledger version where an amendment becomes enabled, the rules don't change mid-ledger. After the ledger is closed, the next ledger uses the new rules as defined by any new amendments that applied.
+
+### Amendments ID Format
+
+The `Amendments` object ID is the hash of the `Amendments` space key (`0x0066`) only. This means that the ID of the `Amendments` object in a ledger is always:
+
+```
+7DB0788C020F02780A673DC74757F23823FA3014C1866E72CC4CD8B226CD6EF4
+```
+
+(Don't mix up the ID of the `Amendments` ledger object type with the Amendment ID of an individual amendment.)
diff --git a/content/ledger-objects/check.md b/content/ledger-objects/check.md
@@ -0,0 +1,54 @@
+## Check
+[[Source]<br>](https://github.com/ripple/rippled/blob/develop/src/ripple/protocol/impl/LedgerFormats.cpp#L158 "Source")
+
+_Requires the [Checks Amendment](reference-amendments.html#checks)._
+
+A `Check` object describes a check, a potential pull payment, waiting to be cashed. (The potential payment has already been approved by its sender.) Example `Check` object:
+
+```json
+{
+  "Account": "rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo",
+  "Destination": "rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy",
+  "DestinationNode": "0000000000000000",
+  "DestinationTag": 1,
+  "Expiration": 570113521,
+  "Flags": 0,
+  "InvoiceID": "46060241FABCF692D4D934BA2A6C4427CD4279083E38C77CBE642243E43BE291",
+  "LedgerEntryType": "Check",
+  "OwnerNode": "0000000000000000",
+  "PreviousTxnID": "5463C6E08862A1FAE5EDAC12D70ADB16546A1F674930521295BC082494B62924",
+  "PreviousTxnLgrSeq": 6,
+  "SendMax": "100000000",
+  "Sequence": 2,
+  "index": "49647F0D748DC3FE26BDACBC57F251AADEFFF391403EC9BF87C97F67E9977FB0"
+}
+```
+
+A `Check` object has the following fields:
+
+| Field               | JSON Type        | [Internal Type][] | Description     |
+|:--------------------|:-----------------|:------------------|:----------------|
+| `LedgerEntryType`   | String           | UInt16            | The value `0x0043`, mapped to the string `Check`, indicates that this object is a Check object. |
+| `Account`           | String           | Account           | The sender of the Check. Cashing the Check debits this address's balance. |
+| `Destination`       | String           | Account           | The intended recipient of the Check. Only this address can cash the Check, using a [CheckCash transaction][]. |
+| `Flags`             | Number           | UInt32            | No flags are defined for Checks, so this value is always `0`. |
+| `SendMax`           | String or Object | Amount            | The maximum amount of currency this Check can debit the sender. If the Check is successfully cashed, the destination is credited in the same currency for up to this amount. |
+| `Sequence`          | Number           | UInt32            | The sequence number of the [CheckCreate transaction][] that created this check. |
+| `OwnerNode`         | String           | UInt64            | A hint indicating which page of the sender's owner directory links to this object, in case the directory consists of multiple pages. **Note:** The object does not contain a direct link to the owner directory containing it, since that value can be derived from the `Account`. |
+| `DestinationNode`   | String           | UInt64            | _(Optional)_ A hint indicating which page of the destination's owner directory links to this object, in case the directory consists of multiple pages. |
+| `Expiration`        | Number           | UInt32            | (Optional) Indicates the time after which this Check is considered expired. See [Specifying Time](reference-rippled.html#specifying-time) for details. |
+| `InvoiceID`         | String           | Hash256           | _(Optional)_ Arbitrary 256-bit hash provided by the sender as a specific reason or identifier for this Check. |
+| `SourceTag`         | Number           | UInt32            | _(Optional)_ An arbitrary tag to further specify the source for this Check, such as a hosted recipient at the sender's address. |
+| `DestinationTag`    | Number           | UInt32            | _(Optional)_ An arbitrary tag to further specify the destination for this Check, such as a hosted recipient at the destination address. |
+| `PreviousTxnID`     | String           | Hash256           | The identifying hash of the transaction that most recently modified this object. |
+| `PreviousTxnLgrSeq` | Number           | UInt32            | The [index of the ledger](#ledger-index) that contains the transaction that most recently modified this object. |
+
+
+### Check ID Format
+[[Source]<br>](https://github.com/ripple/rippled/blob/develop/src/ripple/protocol/impl/Indexes.cpp#L193-L200 "Source")
+
+The ID of a `Check` object is the [SHA-512Half](#sha512half) of the following values put together:
+
+* The Escrow space key (`0x0043`)
+* The AccountID of the sender of the [CheckCreate transaction][] that created the `Check` object
+* The Sequence number of the [CheckCreate transaction][] that created the `Check` object