Marble Sort Level 173 — Walkthrough and Solution

Level 173 is the double key trap and bottom row bait. The Double Key Trap and Bottom Row Bait make this level a sneaky puzzle — beat it by clearing Brown first, then Black, before touching anything else.

Level173
DifficultyMedium
Priority routePurple → Pink
Watch forPurple

▶ Video walkthrough of Marble Sort level 173, then the step-by-step below.

⚡ Quick clear

Purple → Pink. Only drop a colour when its box is ready.

Marble Sort Level 173 is a tricky puzzle that hides its real goal behind a tempting array of easy-looking marbles. The key to winning is to ignore the bright Purple, Pink, and Green marbles at the bottom until you've cleared the Brown and Black boxes, which unlocks the rest of the board. Start by dropping the Brown marble from the center bottom into its box, then focus on the Black marbles hidden under the lock and key mechanism.

The top tray is divided into five columns, each topped by a tunnel that releases three extra marbles later. The middle columns are blocked by two horizontal Yellow keys that lock off the center area. The bottom row of the top tray contains Purple, Pink, Brown, Bright Green, and Red from left to right, but only the Brown marble matches an active front box at the start. The front boxes demand Black, Brown, Yellow, and White from left to right, so most of the bottom row is a trap designed to clog your conveyor belt.

Marble Sort Level 173 Walkthrough

Your active front boxes are, from left to right: Black, Brown, Yellow, and White. The bottom row of the top tray holds Purple, Pink, Brown, Bright Green, and Red, but only Brown is useful immediately. The other four colors are decoys that will jam your conveyor if you grab them too early.

The biggest trap is the Purple marble on the far left bottom. It looks safe, but the Purple box is buried behind the Black box, so dropping it early wastes a slot. Similarly, Pink and Green are not needed until much later. The only safe early move is to clear the Brown marble and then work on the Black box.

How to Beat Marble Sort Level 173 — Step-by-Step

Phase one: Clear the Brown and Break the Lock

  1. Tap the Brown marble in column 3 of the bottom row and send it to the middle-left Brown box.
  2. Leave the Purple, Pink, and Green bottom-row marbles alone for now.
  3. After the Brown box clears, the next box in that queue is Red, so tap the Red marble in column 5 and drop it into the Red box.
  4. Now look above the Purple bait in column 1 — there is a Yellow marble in row 2. Park the Purple marble on the conveyor (just one is fine) to clear a path, then grab that Yellow and feed it to the middle-right Yellow box.
  5. With Brown and Yellow boxes progressing, dig into the center grid to find Black marbles, especially around columns 3 and 5, and route them to the far-left Black box.
  6. Clearing the Black box will eventually release the pegs holding the two Yellow keys. Once both keys break, the center opens up.

Phase two: Open the Center and Clear Purple

  1. After the keys break, the center marbles are accessible, but don't panic-click them.
  2. Clearing the Black box moves the Purple box to the front. Now use that Purple marble you parked earlier, and send all remaining Purple marbles into that box.
  3. When the Purple box clears, a Green box appears. Take the Bright Green marble from column 4 and drop it into that box.
  4. Continue clearing the center grid, feeding marbles to the active boxes as they appear.

Phase three: Survive the Tunnel Flood

  1. As you clear the top row, the five tunnels will start releasing their hidden marbles. Do not strip the top row completely, or all tunnels will dump at once.
  2. Focus on the rightmost boxes, especially the White box, to open up a Purple slot for the upcoming tunnel drops.
  3. Pull Light Blue marbles from the tunnels only when the Light Blue box is active or about to be active.
  4. Keep at least three conveyor slots empty at all times. If a tunnel drops a color you don't need, leave it on the top row until its box is available.
  5. Clear the bottom boxes one by one, and the final marbles will sort themselves.

Tips & tricks

  • Always prioritize the Brown and Black boxes first — they unlock the rest of the board.
  • Use the conveyor sparingly; only park a marble when it's absolutely necessary to reach a key one.
  • Monitor the tunnel countdown — if you see a tunnel about to open, make sure you have space to handle the new marbles.

Common mistakes

  • Grabbing the Purple marble too early, which clogs the conveyor for a long time.
  • Opening all five tunnels at once, causing an overwhelming flood of marbles.
  • Ignoring the Black box and instead clearing easy marbles, which leads to a deadlock.

Marble Sort Level 173 FAQ

Why does my Conveyor Belt flood on Marble Sort Level 173?

Your Conveyor Belt floods because you likely grabbed bait marbles like Purple or Pink early, which have no available box until much later, or because you opened all five tunnels at once, dumping too many marbles at once.

Which color do I clear first on Marble Sort Level 173?

Clear the Brown marble first, then focus on the Black box, as these are the only safe early moves that unlock the rest of the board.

How many moves does it take to clear Marble Sort Level 173?

The number of moves varies based on the tunnel drops, but an efficient run typically takes around 150 moves if you follow the correct sequence and avoid mistakes.

Do I need boosters to beat Marble Sort Level 173?

No boosters are required if you follow the walkthrough, but a shuffle or undo can help if you accidentally make a wrong move.

What happens if I grab the Purple marble too early on Marble Sort Level 173?

If you grab the Purple marble too early, it will sit on your Conveyor Belt for half the level, since the Purple box is buried behind the Black box, limiting your space and making it much harder to sort other marbles.

Get the Official Game

⬇ Download Marble Sort

Back to the full Marble Sort level list.