# How is a Gin Rummy hand scored if both the knocking and defending player have Gin?

I am playing with the Big Gin variant, which is not part of the base game.

Say I pick up a card from the deck which makes me a Gin hand. Only, I don't realize it due to say, misreading my hand, or I questionably decide to try for Big Gin for extra points, and simply discard my remaining deadwood card without knocking.

My opponent now draws from the deck, makes Gin, and knocks.

How is the hand scored?
In particular:

1. Does the defending player receive the Gin bonus?
2. Since the defending player has equaled the knocking player's deadwood count (0), do they receive the undercut bonus even though the knocking player made Gin?
If so, does the knocking player still receive the Gin bonus?

Your opponent gets 25 points plus 0 points. You do not get a chance to undercut. According to Pagat:

A player who goes gin can never be undercut.

You do not get a gin bonus because you did not declare gin. You don't have a chance to declare gin because play ended. Play ended because your opponent knocked. Again from Pagat, emphasis mine:

You can end the play at your turn if [...] Ending the play in this way is known as knocking [...]

• The original revision of this answer was waaaay off. Some sources (rummy.com) call "going gin" and "knocking" two totally different things, which really confused me when I read the question. Other sources (Pagat.com, Wikipedia.com) label going gin a special case of knocking - knocking for zero. I could use a little help in establishing the authoritativeness of Pagat. Anyone? – Rainbolt Jan 9 '15 at 14:40
• You'll have to forgive me if my terminology is bad; I'm a complete beginner to the game. Some excerpts from Harbin's "Waddington's Family Card Games", from which I learnt the game: "Suppose that you decide to 'knock' or go down with 6 points against you..." and later: "If you go down with no unmatched cards at all, this is 'going gin' and you call 'Gin'." Perhaps "going down" was the phrase I was looking for, rather than "knock", where knocking and going gin are the two special cases of going down? Other sources seem to think "going down" is simply another term for knocking. – itchimus Jan 10 '15 at 4:16
• It turns out rummy.com/ginrummy.html answers this pretty specifically - more clearly than the Pagat source you've quoted, though it does agree with you. Search for "Gin Scoring" on that page. If you're happy referencing that source in your answer, I'll gladly accept your answer. – itchimus Jan 10 '15 at 4:22