Hello Kitty no Happy House Server Technical Documentation 0.2
March 04, 2019
Shonumi aka D.S. Baxter

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1. Introduction
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Hello Kitty no Happy House is a Game Boy Color title featuring furniture collection, minigames, and online communication. The game revolves around interacting with Hello Kitty, gaining new furniture, and decorating the "Happy House". As it concerns the Mobile Adapter GB, Hello Kitty no Happy House boasts basic email capabilities. Through the email service, users could share different furniture as presents.


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2. Server Structure
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Hello Kitty no Happy House is not known to access any resource via HTTP. Instead, it simply communicates with a SMTP server and POP3 server for sending and receiving email respectively.


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3. Email
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Email can be sent and received in Hello Kitty no Happy House, much like Mobile Trainer. The game offers similar tools to write the email, helping users fill out subjects, addresses, and content, and viewing the mailbox for received items. The game also sends "presents" to another user via email. The standard email format looks something like this (note that xxxx, yyyy, and zzzz parts are not exact lengths, consider them as variables):

From: =?ISO-2022-JP?xxxxxxxxxxxxxxxxxxxxxxxx <yyyy@zzzz.dion.ne.jp>
To: =?ISO-2022-JP?xxxxxxxxxxxxxxxxxxxxxxxx <yyyyyyyyy>
Subject: =?ISO-2022-JP?xxxxxxxxxxxxxxxxxxxxxxxx
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-2022-JP"
Content-Transfer-Encoding: 7bit
X-Mailer: Hello Kitty Happy House
X-Game-title: HKITTY_HH
X-Game-code: CGB-BK7J-00
[content of email]

The game uses two additional custom SMTP email headers to send furniture to another player. These headers are parsed for a 3-letter ASCII code which determines the item received. After the "X-Game-code" header, the following would be inserted before the content of the email:

X-GBmail-type: exclusive
X-HKH-HOUSE: [3-letter code]

The codes appear to be simple, e.g. "AAE" for a framed picture and "AIG" for a green rug.


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4. Item Codes
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Below are a list of 3-letter codes and the items they generate when used in the email header. If the game does not recognize the code, a present icon will appear next to the email, but no item is actually received.

The 3-letter codes act as stand-ins for numbers (A = 0 ... Z = 25) in a weird mix of Base-10 and Base-26. The position of each letter multiplies its value by 10. As a result, some values can have multiple encodings that the game will accept. For example, the number "20" can be enocoded as "AAU" or "ABK" or "ACA".

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Codes			| Item
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AAB			Heart Clock
AAC			Pendulum Clock
AAD			Futuristic Clock
AAE			Landscape Painting
AAF			Pop Art Painting
AAG			Kitty Elastomer
AAH			Bronze Angel Statue
AAI 			Bronze Goddess Statue
AAJ			Bronze Kitty Statue
AAK	ABA		Hanging Scroll
AAL	ABB		Dragon Pennant
AAM	ABC		Noble Pennant
AAN	ABD		Wide TV
AAO	ABE		Cute TV
AAP	ABF		Wall-mounted TV
AAQ	ABG		Digital Component Stereo
AAR	ABH		Component Stereo
AAS	ABI		Gramophone
AAT	ABJ		Massage Chair 1
AAU	ABK	ACA	Massage Chair 2
AAV	ABL	ACB	Relaxing Chair
AAW	ABM	ACC	Globe
AAX	ABN	ACD	Cosmic Globe
AAY	ABO	ACE	Miniature House
AAZ	ABP	ACF	Pink Chest
ABQ	ACG		Japanese Drawer
ABR	ACH		Toy Case
ABS	ACI		Japanese Vase
ABT	ACJ		Western Vase
ABU	ACK	ADA	Arabian Vase
ABV	ACL	ADB	Tetra Aquarium
ABW	ACM	ADC	Turtle Aquarium
ABX	ACN	ADD	Arowana Aquarium
ABY	ACO	ADE	Floor Light
ABZ	ACP	ADF	Standing Light
ACQ	ADG		Mood Light
ACR	ADH		Doggy Doll
ACS	ADI		Sheep Doll
ACT	ADJ		Lion Doll
ACU	ADK	AEA	Puppet Storage Box
ACV	ADL	AEB	Robot Base
ACW	ADM	AEC	Doll House
ACX	ADN	AED	Magazine Rack
ACY	ADO	AEE	Letter Rack
ACZ	ADP	AEF	Bookstand
ADQ	AEG		Hat Stand
ADR	AEH		Coat Stand
ADS	AEI		Dear Daniel Doll
ADT	AEJ		Pink Living Room Furniture
ADU	AEK	AFA	Blue Living Room Furniture
ADV	AEL	AFB	White Living Room Furniture
ADW	AEM	AFC	Thai Living Room Furniture
ADX	AEN	AFD	Chinese Living Room Furniture
ADY	AEO	AFE	Asian Living Room Furniture
ADZ	AEP	AFF	Japanese Living Room Furniture
AEQ	AFG		Wooden Japanese Chestnut Living Room Furniture
AER	AFH		Wajima Lacquer Living Room Furniture
AES	AFI		Cozy Living Room Furniture
AET	AFJ		Checkered Living Room Furniture
AEU	AFK	AGA	Pop Living Room Furniture
AEV	AFL	AGB	Old Living Room Furniture
AEW	AFM	AGC	Old-fashioned Living Room Furniture
AEX	AFN	AGD	Antique Living Room Furniture
AEY	AFO	AGE	Heart-themed Living Room Furniture
AEZ	AFP	AGF	Apple-themed Living Room Furniture
AFQ	AGG		Flower-themed Living Room Furniture
AFR	AGH		Red Kotatsu
AFS	AGI		Blue Kotatsu
AFT	AGJ		Yellow Kotatsu
AFU	AGK	AHA	Extravagant Living Room Furniture
AFV	AGL	AHB	Elegant Living Room Furniture
AFW	AGM	AHC	Hello Kitty-themed Living Room Furniture
AFX	AGN	AHD	Red Art Studio
AFY	AGO	AHE	Blue Art Studio
AFZ	AGP	AHF	Elegant Art Studio
AGQ	AHG		Model Train
AGR	AHH		Toy Blocks
AGS	AHI		Playing House Set
AGT	AHJ		Standing Table
AGU	AHK	AIA	Flower-pattern Table
AGV	AHL	AIB	Glass Table
AGW	AHM	AIC	Japanese Flower Arranged Desk
AGX	AHN	AID	Flower Arrangement
AGY	AHO	AIE	Bonsai
AGZ	AHP	AIF	Red Carpet
AHQ	AIG		Green Carpet
AHR	AIH		Blue Carpet (says blue, looks purple)
AHS	AII		Blue Playground Slide
AHT	AIJ		Red Playground Slide (says red, looks pink)
AHU	AIK	AJA	White Playground Slide
AHV	AIL	AJB	Easy Chair
AHW	AIM	AJC	Tranquil Chair
AHX	AIN	AJD	Relaxing Chair
AHY	AIO	AJE	Gold Tearoom
AHZ	AIP	AJF	Silver Tearoom
AIQ	AJG		Play Set
AIR	AJH		Changing-clothes Box
AIS	AJI		Changing-clothes Case
AIT	AJJ		Strange Box
AIU	AJK	AKA	Somersault Platform
AIV	AJL	AKB	Jump Sheet
AIW	AJM	AKC	Trampoline
AIX	AJN	AKD	Pink Refrigerator
AIY	AJO	AKE	Wood-grain Refrigerator
AIZ	AJP	AKF	Play Refrigerator
AJQ	AKG		White Iron
AJR	AKH		Green Iron
AJS	AKI		Purple Iron
AJT	AKJ		Brown Builder (workout set)
AJU	AKK	ALA	Purple Builder (workout set)
AJV	AKL	ALB	Green Builder (workout set)
AJW	AKM	ALC	Brown Runner (treadmill)
AJX	AKN	ALD	Red Runner (treadmill, says red, looks pink)
AJY	AKO	ALE	Blue Runner (treadmill)
AJZ	AKP	ALF	Flower Piano
AKQ	ALG		Star Piano
AKR	ALH		Classic Piano
AKS	ALI		Crystal Ball Set
AKT	ALJ		Fortune-Telling Set
AKU	ALK	AMA	Tarot Card Divination
