Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
Builders who report a missing piece often find it in one of these places. Tick each one off as you look.
Look-alike colors in this set
These parts appear in this set in two colors that are easy to confuse. If you are one short in one color,
check whether it went in where the other color belongs. Each color has its own element ID in the parts list
at the back of the instructions.
Bracket 1 x 2 - 2 x 2 InvertedTan ×4Dark Tan ×2Tan is lighter than Dark Tan.
Plate 1 x 2Tan ×7Dark Tan ×2Tan is lighter than Dark Tan.
Plate 1 x 4Tan ×3Dark Tan ×3Tan is lighter than Dark Tan.
Plate 1 x 2Black ×4Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Plate 2 x 6Black ×6Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Plate 2 x 8Black ×1Dark Bluish Gray ×3Black is darker than Dark Bluish Gray.
4 more look-alike pairs
Plate Special 1 x 2 Rounded with 2 Open StudsBlack ×4Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Black ×15Dark Bluish Gray ×4Black is darker than Dark Bluish Gray.
Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Half Hollow Anti-stud] - Updated VersionBlack ×4Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Tile Special 1 x 2 Grille with Bottom GrooveBlack ×1Dark Bluish Gray ×6Black is darker than Dark Bluish Gray.
LEGO's request form asks for the set number (71423) and each piece's element ID, both listed above.
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Piece checklist
Plates
156 pieces
Plate 1 x 2BlackPart 3023Element 302326Also in Dark Bluish Gray×4
Plate 1 x 4BlackPart 3710Element 371026×3
Plate 1 x 8BlackPart 3460Element 346026×1
Plate 2 x 12BlackPart 2445Element 244526×1
Plate 2 x 2BlackPart 3022Element 302226×1
Plate 2 x 6BlackPart 3795Element 379526Also in Dark Bluish Gray×6
Plate 2 x 8BlackPart 3034Element 303426Also in Dark Bluish Gray×1
Plate 3 x 3BlackPart 11212Element 6174917×2
Plate 4 x 10BlackPart 3030Element 303076 or 303026×1
Plate 4 x 6BlackPart 3032Element 303226×2
Plate 1 x 1Bright Light OrangePart 3024Element 6073040 or 6028740×2
Plate 1 x 1Dark Bluish GrayPart 3024Element 4210719×2
Plate 1 x 10Dark Bluish GrayPart 4477Element 4257526 or 4210816×2
Plate 1 x 2Dark Bluish GrayPart 3023Element 4211063Also in Black×2
Plate 2 x 3Dark Bluish GrayPart 3021Element 4211043×2
Plate 2 x 6Dark Bluish GrayPart 3795Element 4211002Also in Black×1
Plate 2 x 8Dark Bluish GrayPart 3034Element 4210997Also in Black×3
Plate 4 x 4 CornerDark Bluish GrayPart 2639Element 4539429×4
Plate 2 x 4Dark OrangePart 3020Element 4535928 or 4164449×1
Plate 2 x 2Dark RedPart 3022Element 4585479 or 4163160×4
Plate 1 x 2Dark TanPart 3023Element 4528604 or 4497082Also in Tan×2
Plate 1 x 4Dark TanPart 3710Element 4626904 or 4497088Also in Tan×3
Plate 2 x 2 CornerDark TanPart 2420Element 4550168×6
Plate 2 x 3Dark TanPart 3021Element 6035540 or 6015192×1
Plate 1 x 3GreenPart 3623Element 4107758 or 362328×1
Plate 2 x 2GreenPart 3022Element 302228×2
Plate 1 x 1Light AquaPart 3024Element 6058016 or 6015040×4
Plate 1 x 4Light AquaPart 3710Element 6141592 or 6015057×2
Plate 1 x 1Light Bluish GrayPart 3024Element 4211399×4
Plate 1 x 2Light Bluish GrayPart 3023Element 4211398 or 3023194×5
Plate 1 x 6Light Bluish GrayPart 3666Element 4211438×4
Plate 1 x 8Light Bluish GrayPart 3460Element 4211425×1
Plate 2 x 12Light Bluish GrayPart 2445Element 4211360×4
Plate 2 x 2Light Bluish GrayPart 3022Element 4211397×2
Plate 2 x 4Light Bluish GrayPart 3020Element 4211395×4
Plate 2 x 6Light Bluish GrayPart 3795Element 4211452 or 3795194×1
Plate 2 x 8Light Bluish GrayPart 3034Element 4211406×1
Plate 1 x 3OrangePart 3623Element 6147047 or 4513281×2
Plate 1 x 4OrangePart 3710Element 4118782×3
Plate 2 x 6OrangePart 3795Element 4121741×4
Plate 1 x 2RedPart 3023Element 302321×2
Plate 1 x 3RedPart 3623Element 362321×1
Plate 1 x 4RedPart 3710Element 371021×1
Plate 2 x 12RedPart 2445Element 4255035 or 4161545×3
Plate 2 x 2RedPart 3022Element 4613974 or 302221×4
Plate 2 x 3RedPart 3021Element 302121×1
Plate 2 x 4RedPart 3020Element 302021×1
Plate 2 x 8RedPart 3034Element 303421×4
Plate 4 x 4 CornerRedPart 2639Element 6430333 or 4519523×1
Plate 4 x 6RedPart 3032Element 303221×1
Plate 1 x 1Reddish BrownPart 3024Element 4221744×2
Plate 2 x 10Reddish BrownPart 3832Element 4211214×1
Plate 2 x 2 CornerReddish BrownPart 2420Element 4211257×2
Plate 2 x 6Reddish BrownPart 3795Element 4211247×1
Plate 1 x 2TanPart 3023Element 4113917 or 302305Also in Dark Tan×7
Plate 1 x 4TanPart 3710Element 4113233 or 371005Also in Dark Tan×3
Plate 1 x 2WhitePart 3023Element 6552100 or 6548261×13
Plate 2 x 2WhitePart 3022Element 6552099 or 6548260×3
Plate 2 x 4WhitePart 3020Element 6552098 or 302001×1
Plate 1 x 4YellowPart 3710Element 371024×2
Plate 1 x 6YellowPart 3666Element 366624×1
Plates Special
153 pieces
Bracket 1 x 2 - 1 x 2BlackPart 99781Element 6016172×2
Bracket 1 x 2 - 2 x 2BlackPart 44728Element 6117973 or 6048855×4
Bracket 1 x 2 - 2 x 2 InvertedBlackPart 99207Element 6000650×5
Plate Special 1 x 2 [Side Handle Closed Ends]BlackPart 48336Element 4225201×1
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)BlackPart 15573Element 6092585Also in Dark Bluish Gray×15
Plate Special 1 x 2 with Bar Up [Horizontal Arm 5mm]BlackPart 88072Element 6261348 or 4569733×2
Plate Special 1 x 2 with Clips Horizontal [Open O Clips]BlackPart 60470bElement 6310268 or 4556158×1
Plate Special 1 x 2 with Pin Hole UnderneathBlackPart 18677Element 6192309 or 6167497×4
Plate Special 2 x 2 with 2 Pin HolesBlackPart 2817Element 281726×2
Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Half Hollow Anti-stud] - Updated VersionBlackPart 4304Element 6469445Also in Dark Bluish Gray×4
Plate Special 2 x 4 with 2 Pin HolesBlackPart 26599Element 6194233×3
Plate Special 3 x 4 with 1 x 4 Center Studs [Plain]BlackPart 88646Element 6076678 or 4571146×1
Plate Special Round 2 x 2 with Center Stud (Jumper Plate)BlackPart 18674Element 6195325×6
Plate Special Round 2 x 2 with Pin Hole and 4 Bars UpBlackPart 98284Element 6313508 or 4650145×1
Technic Plate 2 x 6 [5 Holes]BlackPart 32001Element 3200126×1
Technic Plate Rotor 6 Blade with Clip Ends Connected [aka Water Wheel] - Solid StudsBlackPart 69984Element 6345465×2
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)BluePart 15573Element 6092582×1
Plate Special 2 x 2 with Groove and Center Stud (Jumper)BluePart 87580Element 6126049 or 4565319×1
Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Half Hollow Anti-stud] - Updated VersionBluePart 4304Element 6469450×1
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Bright Light OrangePart 15573Element 6122504×1
Bracket 1 x 2 - 1 x 2 InvertedDark Bluish GrayPart 99780Element 6000606×2
Plate Special / Shield Rectangular with 4 Studs, HandleDark Bluish GrayPart 30166Element 6258991×2
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Dark Bluish GrayPart 15573Element 6092572Also in Black×4
Plate Special 1 x 2 with Pin Hole on TopDark Bluish GrayPart 11458Element 6019987×2
Plate Special 1 x 2, Top Clip [Open O]Dark Bluish GrayPart 44861Element 6344754×4
Plate Special 2 x 2 with Groove and Center Stud (Jumper)Dark Bluish GrayPart 87580Element 6126083 or 4565322×4
Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Half Hollow Anti-stud] - Updated VersionDark Bluish GrayPart 4304Element 6469463Also in Black×2
Plate Special 1 x 1 with Clip Light, Bar Hole [Thick Ring]Dark RedPart 4081bElement 6282000 or 6131833×1
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Dark RedPart 15573Element 6092597×2
Bracket 1 x 2 - 2 x 2 InvertedDark TanPart 99207Element 6330148Also in Tan×2
Plate Special 1 x 3 with 2 Studs (Jumper) with 2 White Squares on Side PrintDark TurquoisePart 34103pr0001Element 6334686×1
Plate Special 1 x 3 with 2 Studs with Groove and Inside Stud Holder (Jumper)Dark TurquoisePart 34103Element 6334098×1
Plate Special Round 1 x 2 Half Circle with Stud (Jumper)GreenPart 1745Element 6510059 or 6424859×2
Bracket 1 x 2 - 1 x 2 InvertedLight Bluish GrayPart 99780Element 6004990×1
Plate Special 1 x 2 5.9mm Centre Side Towball SocketLight Bluish GrayPart 14704Element 6414561 or 6338165×2
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Light Bluish GrayPart 15573Element 6066097 or 4211451×2
Plate Special 1 x 2 with Pin Hole On SideLight Bluish GrayPart 3172Element 6438836×2
Plate Special 1 x 3 with 2 Studs with Groove and Inside Stud Holder (Jumper)Light Bluish GrayPart 34103Element 6211969×1
Plate Special 1 x 4 with 2 Studs with Groove [New Underside]Light Bluish GrayPart 41740Element 6257593×2
Plate Special 2 x 2 Splat Gear, 6 TeethMedium AzurePart 35442Element 6271207×1
Bracket 1 x 2 - 1 x 2 InvertedOrangePart 99780Element 6218368×2
Bracket 1 x 2 - 2 x 2 InvertedOrangePart 99207Element 6061676×2
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)OrangePart 15573Element 6092599×2
Plate Special 2 x 2 with Only 2 studsOrangePart 33909Element 6400037×2
Bracket 1 x 2 - 2 x 2 InvertedRedPart 99207Element 6001806×3
Plate Special 1 x 2 with Pin Hole on TopRedPart 11458Element 6099736×2
Plate Special 1 x 4 with 2 Studs with Groove [New Underside]RedPart 41740Element 6256923×2
Plate Special Round 2 x 2 with Center Stud (Jumper Plate)RedPart 18674Element 6132541×1
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Reddish BrownPart 15573Element 6092590×4
Plate Special 1 x 2 with Handle on End [Closed Ends]Reddish BrownPart 60478Element 6102975×2
Plate Special Round 1 x 2 Half Circle with Stud (Jumper)Reddish BrownPart 1745Element 6510060 or 6428178×2
Bracket 1 x 2 - 2 x 2 InvertedTanPart 99207Element 6174925Also in Dark Tan×4
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)TanPart 15573Element 6092587×1
Plate Special 1 x 2 with Clip Horizontal on SideTanPart 11476Element 6313119 or 6177314×1
Bracket 1 x 2 - 1 x 2WhitePart 99781Element 6552141 or 6548275×2
Bracket 1 x 2 - 1 x 2 InvertedWhitePart 99780Element 6548278 or 6070698×2
Bracket 1 x 2 - 1 x 4 [Rounded Corners at Bottom, Square Corners at Top]WhitePart 28802Element 6548284 or 6168618×1
Plate Special 1 x 1 with ToothWhitePart 49668Element 6601935 or 4224792×4
Plate Special 1 x 1 with Vertical ToothWhitePart 15070Element 6615559 or 6046905×2
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)WhitePart 15573Element 6550152 or 6051511×2
Plate Special 1 x 2 with Handle on End [Closed Ends]WhitePart 60478Element 6552131 or 4515364×1
Plate Special 1 x 2 with Pin Hole on TopWhitePart 11458Element 6632146 or 6057414×2
Plate Special 1 x 2 with Three Teeth [Tri-Tooth]WhitePart 15208Element 6046381×4
Plate Special 1 x 8 with Door RailWhitePart 4510Element 6619290 or 4501853×2
Plate Special 8 x 8 x 2/3 Octagon with RimWhitePart 67929Element 6318110×1
Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Half Hollow Anti-stud] - Updated VersionYellowPart 4304Element 6469455×2
Bricks Sloped
128 pieces
Brick Sloped Inverted 45° 2 x 1BlackPart 3665Element 366526×4
Rock Brick 8 x 8 x 6Dark Bluish GrayPart 23996Element 6138752×4
Plate Special 8-Sided Crystal/Gem 1 x 1 x 2/3Opal Trans-ClearPart 65092Element 6514349 or 6287309×1
Rock / Ice / Flames, 1 x 4 with 2 Studs on the EdgesTrans-OrangePart 70880Element 6514402 or 6325390×2
Supports, Girders and Cranes
7 pieces
Support 1 x 6 x 10 Girder TriangularBlackPart 64449Element 6223603 or 4659404×1
Support Half Round 2 x 4 x 13BlackPart 1749Element 6507802 or 6449621×4
Support 2 x 2 x 13 with 5 Pin HolesLight Bluish GrayPart 91176Element 6339298×2
Energy Effects
6 pieces
Wave / Flame Small with PinTrans-OrangePart 37775Element 6514274 or 6357747×6
Panels
5 pieces
Panel 1 x 4 x 2 with Side Supports - Hollow StudsLight Bluish GrayPart 14718Element 6061675×1
Panel 1 x 6 x 5Light Bluish GrayPart 59349Element 4527174×2
Panel 3 x 3 x 6 Corner Wall without Bottom IndentationsLight Bluish GrayPart 87421Element 6387879 or 4563698×2
Technic Beams
5 pieces
Technic Beam 1 x 11 ThickBlackPart 32525Element 6029578 or 4534909×2
Technic Beam 1 x 7 ThickDark Bluish GrayPart 32524Element 4495931 or 4210752×2
Technic Beam 1 x 7 ThickRedPart 32524Element 4495933 or 4162098×1
Wheels and Tyres
4 pieces
Wheel 11 x 8 with Center GrooveLight Bluish GrayPart 42610Element 4211758×4
Technic Special
3 pieces
Technic Plate 1 x 5 with Smooth Ends, 4 Studs and Centre Axle HoleDark Bluish GrayPart 32124Element 6306725×2
Technic Ball JointRedPart 32474Element 4290714 or 4178640×1
Animal / Creature Body Parts
2 pieces
Animal Body Part, Barb / Claw / Tooth / Talon / Horn, MediumTanPart 87747Element 6314377×2
Minifig Lower Body
2 pieces
Feet, 2 x 2 x 2/3, Front Left Foot Forward with 4 Studs on TopDark TurquoisePart 79750Element 6357991×1
Feet, 2 x 2 x 2/3 with 4 Studs on TopReddish BrownPart 66858Element 6300006×1
Minifig Upper Body
2 pieces
Arm, Short, with Technic PinLight NougatPart 28660Element 6297281×2
Plants & Trees
2 pieces
Plant, Fern 2 x 3 x 2Dark Bluish GrayPart 2682Element 6454351×2
Containers
1 piece
Container Box 2 x 2 x 1 Reinforced Bottom with Chest, Lock PrintLight Bluish GrayPart 2821pr0009Element 6438694×1
Tools
1 piece
Brick and Axle Separator v2.0Dark TurquoisePart 96874Element 6254100×1
Transportation - Sea and Air
1 piece
Propeller with PinBlackPart 54568Element 6305094×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
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pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.