Animal Crossing: New Leaf Duping Bug Guide
by Timrod (v1.02)

This guide covers the methods and practice of how to exploit the duping bug 
in Animal Crossing: New Leaf. Currently, the bug exists in all versions of 
the game, including both the digital and physical copies in all regions. 
It is unknown at this time whether or not the Australian release of the game 
(which has not happened at the time this guide was written) will also contain
the duping bug.

------------------------------------------------------------------------------
Contents (Please read ALL SECTIONS before attempting to dupe anything):
------------------------------------------------------------------------------
#1A: What is the duping bug?
#1B: What are the potential dangers of exploiting this bug?
#2A: How do I use the bug?
#2B: What is the correct timing for using the wi-fi switch?
#3A: What items cannot be duped?


------------------------------------------------------------------------------
#1A: What is the duping bug?
------------------------------------------------------------------------------
The duping bug is an exploit in the game's save system that allows players to
duplicate items, including those that are not re-orderable through the 
catalog machine located in the Nookling store. 

Currently, the bug only works during online sessions - meaning that in order
to use it, you will need internet access on your 3DS and a second town with 
open gates set to online mode. Local wireless will not work.

While the glitch is theoretically possible to accomplish by yourself using
multiple 3DS systems, it is strongly reccomended that you have a second 
player, preferably a trusted friend, to help you due to the strict timing 
required to pull off the glitch.

You should also consider the use of a real-time chat method, such as Steam or 
IRC, to coordinate with the other player. This will give you immediate 
feedback as to whether or not the dupe was successful.


------------------------------------------------------------------------------
#1B: What are the potential dangers of using this bug?
------------------------------------------------------------------------------

The potential dangers of using this bug include, but are not limited to:

- Loss of potentially valuable items if you are hosting.
- Having your items stolen by less-than-scrupulous players. 
- Having your save file corrupted.

While several players claim to have had their savegames corrupted as a result
of the duping glitch, there is no proof that using the glitch in the correct
manner results in savegame corruption. Many players, myself included, have
duped hundreds of items without corruption occurring.

Despite this, I am not responsible for any lost or corrupt data that occurs
as a result of using this glitch.


------------------------------------------------------------------------------
#2A: How do I use the bug?
------------------------------------------------------------------------------

The bug can be used via one of two methods during online play. Both methods 
revolve around the visitor, but one is far safer than the other.

Note that you can duplicate any items that are in your character's inventory
or that are in their storage slots. It is not possible to dupe items inside
of letters - pull them out before entering the host's town. Doing anything
with letters causes the game to make a "mini-save" that will normally cause
the items to stay in the host's town and not be in the visitor's inventory
once the glitch has been used.

Method 1: One-Way Duping

One-Way Duping is the safer method of duplicating items, in that it is 
normally impossible for anyone to lose items using this method. Use this
method when the person visiting the host town has the items to be duped.

Step 1 - Visitor with items to be duped enters Host's town.

Step 2 - The Visitor drops the items to be duped.

Step 3 - After confirming that both players are ready, the Host presses 
Start and chooses the "End the Online Session" option. After ending the 
session, the host does NOTHING. The host should NOT touch their wi-fi switch.

Step 4 - While the game is saving (the blue loading circle has popped up), 
the Visitor turns off their 3DS's wi-fi via the switch, which is located on 
the right side of the system above the SD card slot. 

It is CRUCIAL that the host does NOT touch their wi-fi switch, and that 
neither player attempts to power their 3DS off via the Power button. 
Powering off can and will corrupt save files.

Step 5 - Ideally, the Visitor will get the Resetti error screen and 
return to their town with their items still in their inventory. The host 
should NOT get the Resetti error screen, and will instead go through the
entire saving process to completion. 

Step 6 - If done correctly, the Visitor should arrive back in their town
with their items still in their inventory. The Host should have the items the
Visitor dropped on the ground where they were left at the time the session 
was ended.

******************************************************************************

Method 2: Two-Way Duping

Two-Way Duping is essentially a faster (but riskier) alternative method when 
each player wishes to dupe items the other has. It is risky because if the 
initial save (see Step 3) is skipped, any items the Host has dropped will 
disappear when the Host ends session. 

Step 1 - Visitor with items to be duped enters the Host's town.

Step 2 - The Host drops the items the Visitor wishes to have duped.

Step 3 - Visitor picks up the items. The Host then saves the game via the 
start menu, but does NOT end the online session. It is CRUCIAL that the Host 
saves here, or any items the Host has dropped will be deleted when the 
session is ended.

Step 4 - AFTER THE SAVE, the Visitor drops the items the Host wishes 
to have duped, and any of the host's items the Visitor picked up.

Step 5 - After confirming that both players are ready, the Host presses Start 
and chooses the "End the Online Session" option. After ending the session, 
the Host does NOTHING. The host should not touch their wi-fi switch.

Step 6 - While the game is saving (the blue loading circle has popped up),
the visitor turns off their 3DS's wi-fi via the switch, which is located on 
the right side of the system above the SD card slot. It is CRUCIAL that 
the host does NOT touch their wi-fi switch,  and that neither player attempts
to power their 3DS off via the Power button. Powering off can and will result 
in corrupt save files on one or both ends.

Step 7 - Ideally, the Visitor will get the Resetti error screen, and return 
to their town with their items still in their inventory. The host should NOT 
get the Resetti error screen, and will instead go through the entire saving 
process to completion.

Step 8 - If done correctly, the Visitor should arrive back in their town with
their items still in their inventory. The Host should have both the items they
dropped for the Visitor, and the items the Visitor dropped for duplication. 

Two-Way Duping CAN cause items dropped by the Host to be deleted if the save 
in Step 3 is skipped. ALWAYS have a backup of any valuable items ready BEFORE
attempting this method.


------------------------------------------------------------------------------
#2B: What is the correct timing for using the wi-fi switch?
------------------------------------------------------------------------------

There is no one answer to this question. Most players use the position of the
rotating blue dot that loops around a blue circle when the game is saving to
determine when to flip their wi-fi switch. 

My 3DS XL's "sweet spot" is around three-quarters (3/4) of the way through 
the first loop. However, this will not be the case for everyone. Your timing 
may differ wildly depending on how close you are to one of Nintendo's servers. 
In some cases, your sweet spot may be as early as half a loop or 
as late as one full loop. 

The best way to find your "sweet spot" is to do a few duplication attempts
with someone who has the time to open their gates repeatedly, adjusting your
timing by one or two dots at a time. 

Generally, if the Host player is getting the Resetti error screen, it means
the Visitor is switching their wi-fi off too early. 

If neither the Host nor the Visitor get the Resetti screen, but the Visitor 
does not have their items in their inventory once they have returned to their
town, it means the Visitor is switching their wi-fi off too late.

Finding the right spot may take some time and multiple attempts.


------------------------------------------------------------------------------
#3A: Which items cannot be duped using this bug?
------------------------------------------------------------------------------

Any items that cannot be dropped cannot be duplicated. This includes Fish, 
Bugs, items obtained by Diving, and the Mannequins obtained from the Able
sisters and Gracie.

Any items that can be dropped can be duplicated, including once-per-character
items such as the Golden Axe and items that are not purchasable from the 
catalog, such as the furniture from GracieGrace or seasonal/holiday items. 
Characters CAN still obtain once-per-character items that have been duped for
them (ie; a character can still obtain a Golden Watering Can even if one was
duped for them.)