What's the Difference Between Gin Rummy and Rummy?

Short Answer
In standard Rummy, you lay melds on the table during play and can add to opponents' melds. In Gin Rummy, you keep melds hidden until you knock or go Gin. Gin Rummy is faster, typically 2-player, and uses a knocking system with undercut bonuses.

Side-by-Side Comparison

Feature Standard Rummy Gin Rummy
Players 2-6 players 2 players (typically)
Hand Size 7-10 cards (varies) 10 cards
Melding Lay melds on table anytime Keep melds hidden until end
Laying Off Add to anyone's melds during play Defender lays off after knock only
Ending Round Meld all cards or go out Knock (≤10 deadwood) or Gin (0)
Scoring Points for melds, penalty for deadwood Deadwood difference + bonuses
Game Length Can be lengthy Fast (5-10 min per hand)

Why Gin Rummy is Different

Hidden Information

The biggest difference is that Gin Rummy keeps your melds secret. You never reveal your hand until you knock or go Gin. This creates tension and bluffing opportunities that standard Rummy lacks.

The Knocking System

Instead of trying to meld all cards, you can end the round early by "knocking" when your deadwood is 10 points or less. This speeds up gameplay and adds a risk/reward decision.

Undercut Penalty

If you knock and your opponent has equal or less deadwood, they score an undercut bonus (typically 25 points). This doesn't exist in standard Rummy and makes knocking a calculated gamble.

Example

Standard Rummy: You lay down 7-8-9♥ on your turn. Opponent adds 10♥ to your run. Another player adds 6♥.

Gin Rummy: You hold 7-8-9♥ secretly. When you knock with 6 deadwood, opponent sees your melds and can only lay off onto them once.

Which Game is Better?