Row Locking

📖 Strategy Principle

Row locking means: always keep the row (or column) containing your largest tile completely filled.

The importance of this strategy lies in:

• Prevent accidental movement: When a row is filled, tiles in that row won't move in that direction
• Protect the corner tile: Even if you accidentally press the forbidden direction, the largest tile can't move
• Create predictability: You can more easily predict the result of each move

📊 Visual Example

In this example, even if you press "Up", the 512 won't move because the entire bottom row is filled!

Notice there's a gap in the bottom row! If you press "Up" now, 256 might move up and disrupt the entire structure.

❌ Common Mistakes

• Letting gaps appear in key rows: The most common mistake, allowing gaps in the bottom row or side column
• Focusing too much on merging while ignoring row locking: Sometimes trying to merge large tiles accidentally breaks the locked state
• Not knowing when to lock rows: Only locking rows when feeling dangerous, but should always maintain it
• Trying to lock too many rows: Usually you only need to lock one row (the one with the largest tile)

✅ Practical Tips

• Prioritize filling the bottom row: Consider whether each move will create a gap in the bottom row
• Small tiles as "fillers": 2s and 4s contribute little to score but can fill gaps
• Merge at safe moments: If merging will create a gap, first ensure there's a way to immediately fill it
• Plan ahead: Think about how to fill the bottom row back if it becomes empty
• Accept imperfect arrangements: Sometimes the bottom row arrangement isn't perfect (like 512-2-128-64), but as long as it's full, it's safe