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NEC - PC-98 (Neko Project II Kai)


NP2kai is a PC-9801 series core. The NEC PC-9800, also known as the PC-98, were a family of computers made by NEC throughout 1982 to 2000. Despite using Intel x86 chips, MS-DOS and Windows OS, and many other superficial similarities, the series is not IBM compatible. Some PC-98 software may work on an IBM or vice versa, but this is very YMMV. In fact, the introduction of a native Japanese version of standard MS-DOS in the early 90s and subsequent entry of cheaper foreign IBM clones in the Japanese market was the nail in the coffin for the PC-98. They were not released or marketed outside of Japan (besides few attempts such as APC-III and PC-9801FC), but still useful for playing early visual novels and Touhou games.


The Neko Project II Kai core has been authored by

  • Neko Project II Team
  • Tomohiro Yoshidomi

The Neko Project II Kai core is licensed under

A summary of the licenses behind RetroArch and its cores can be found here.


Content that can be loaded by the Neko Project II Kai core have the following file extensions:

  • .d98
  • .zip
  • .98d
  • .fdi
  • .fdd
  • .2hd
  • .tfd
  • .d88
  • .88d
  • .hdm
  • .xdf
  • .dup
  • .cmd
  • .hdi
  • .thd
  • .nhd
  • .hdd
  • .hdn


Required or optional firmware files go in the frontend's system directory.


These firmware files need to be in a directory named 'np2kai' in the frontend's system directory.

Filename Description md5sum
np2kai/font.bmp Needed to display text - Required 7da1e5b7c482d4108d22a5b09631d967
np2kai/FONT.ROM Alt font file - Required 2af6179d7de4893ea0b705c00e9a98d6
np2kai/bios.rom - Required e246140dec5124c5e404869a84caefce
np2kai/itf.rom - Required e9fc3890963b12cf15d0a2eea5815b72
np2kai/sound.rom - Required caf90f22197aed6f14c471c21e64658d
np2kai/bios9821.rom - Optional
np2kai/d8000.rom - Optional
np2kai/2608_BD.WAV YM2608 RYTHM sample - Optional
np2kai/2608_SD.WAV YM2608 RYTHM sample - Optional
np2kai/2608_TOP.WAV YM2608 RYTHM sample - Optional
np2kai/2608_HH.WAV YM2608 RYTHM sample - Optional
np2kai/2608_TOM.WAV YM2608 RYTHM sample - Optional
np2kai/2608_RIM.WAV YM2608 RYTHM sample - Optional


Frontend-level settings or features that the Neko Project II Kai core respects.

Feature Supported
Core Options
RetroArch Cheats
Native Cheats
Disk Control
Crop Overscan


The Neko Project II Kai core's directory name is 'Neko Project II kai'

The Neko Project II Kai core saves/loads to/from these directories.

Frontend's Home directory

  • .bmp (???)

Frontend's State directory

  • 'content-name'.state# (State)

Frontend's System directory

  • np2/np2.cfg (Neko Project II Config file)

Geometry and timing

  • The Neko Project II Kai core's core provided FPS is 56.4.
  • The Neko Project II Kai core's core provided sample rate is 44100Hz.
  • The Neko Project II Kai core's core provided aspect ratio is 8/5.


NP2 menu can FDD/HDD swap.

Mouse is cuptured (hidden/show toggle) by F11 key.

NP2 menu is opened when F12 key

Keep 'end' key down when booting for machine options.

How to set GDC 2.5MHz/5MHz?

  1. Press End key(assigned Help key) + reset
  2. Select 'ディップスイッチ2'(DIP switch 2)

How to use CD drive with MS-DOS 6.2?

Write follow to CONFIG.SYS.


And write follow to AUTOEXEC.BAT.

    A:¥DOS¥MSCDEX.EXE /D:CD_101 /L:Q

Then, you'll can use CD drive as Q drive.

Core options

The Neko Project II Kai core has the following option(s) that can be tweaked from the core options menu. The default setting is bolded.

Settings with (Restart) means that core has to be closed for the new setting to be applied on next launch.

  • PC Model (Restart) [np2kai_model] (PC-9801VX/PC-286/PC-9801VM)

    Awaiting description.

  • CPU Base Clock (Restart) [np2kai_clk_base] (2.4576 MHz/1.9968 MHz)

    Awaiting description.

  • CPU Clock Multiplier (Restart) [np2kai_clk_mult] (4/⅚/8/10/12/16/20/24/30/36/40/42/½)

    Awaiting description.

  • RAM Size (Restart)* [np2kai_ExMemory] (**3/7/11/13/16/32/64/120/230/1)

    Awaiting description.

  • GDC [np2kai_gdc] (uPD7220/uPD72020)

    Awaiting description.

  • Skipline Revisions [np2kai_skipline] (Full 255 lines/ON/OFF)

    Awaiting description.

  • Real Palettes [np2kai_realpal] (OFF/ON)

    Awaiting description.

  • LCD [np2kai_lcd ] (OFF/ON)

    Awaiting description.

  • Sound Board (Restart) [np2kai_SNDboard] (PC9801-86/PC9801-26K + 86/PC9801-86 + Chibi-oto/PC9801-118/PC9801-86 + Mate-X PCM(B460)/Mate-X PCM(B460)/Chibi-oto/Speak Board/Spark Board/Sound Orchestra/Sound Orchestra-V/Sound Blaster 16/AMD-98/Otomi-chanx2/Otomi-chanx2 + 86/None/PC9801-14/PC9801-26K)

    26K: for old games. 86: for newer games.

  • JastSound [np2kai_jast_snd] (OFF/ON)

    Awaiting description.

  • Sound Generator [np2kai_usefmgen] (fmgen/Default)

    Awaiting description.

  • Volume FM [np2kai_volume_F] (0 to 128 in increments of 4. 64 is default.)

    Awaiting description.

  • Volume SSG [np2kai_volume_S] (0 to 128 in increments of 4. 64 is default.)

    Awaiting description.

  • Volume ADPCM [np2kai_volume_A] (0 to 128 in increments of 4. 64 is default.)

    Awaiting description.

  • Volume PCM [np2kai_volume_P] (0 to 128 in increments of 4. 64 is default.)

    Awaiting description.

  • Volume RHYTHM [np2kai_volume_R] (0 to 128 in increments of 4. 64 is default.)

    Awaiting description.

  • Volume CD-DA [np2kai_volume_C] (0 to 255 in increments of 8. 128 is default.)

    Awaiting description.

  • Floppy Seek Sound [np2kai_Seek_Snd] (OFF/ON)

    Awaiting description.

  • Volume Floppy Seek [np2kai_Seek_Vol] (0 to 128 in increments of 4. 80 is default.)

    Awaiting description.

  • Volume Beep [np2kai_BEEP_vol] (3/0/½)

    Awaiting description.

  • Joypad to Mouse Mapping [np2kai_joy2mouse] (OFF/ON)

    Awaiting description.

  • Joypad to Keyboard Mapping [np2kai_joy2key] (OFF/Arrows/Keypad)

    Awaiting description.


The Neko Project II Kai core supports the following device type(s) in the controls menu, bolded device types are the default for the specified user(s):

User 1 device types

  • None - Doesn't disable input.
  • RetroPad - Joypad
  • RetroPad w/Analog - Joypad - There's no reason to switch to this.

Controller tables



The Joy2Key and Joy2Mouse modes can be activated with the 'Joypad to Mouse Mapping' and 'Joypad to Keyboard Mapping' core options.

RetroPad Inputs Joy2Key (Arrows) Joy2Key (Keypad) Joy2Mouse
Z key Z key Mouse left button
Left control key Left control key
Escape key Escape key
Return key Return key
Up arrow key Keypad Up arrow key (8) Move mouse up
Down arrow key Keypad down arrow key (2) Move mouse down
Left arrow key Keypad left arrow key (4) Move mouse left
Right arrow key Keypad right arrow key (6) Move mouse right
X key X key Mouse right button
Space key Space key
Backspace key Backspace key Increase mouse speed
Right shift key Right shift key
NP2 menu key NP2 menu key NP2 menu key


RetroKeyboard Inputs NP2 Keyboard Inputs
Keyboard Backspace NKEY_BACKSPACE
Keyboard Tab NKEY_TAB
Keyboard Return NKEY_RETURN
Keyboard Pause NKEY_STOP
Keyboard Escape NKEY_ESC
Keyboard Space NKEY_SPACE
Keyboard Quote ' NKEY_COLON
Keyboard Comma , NKEY_COMMA
Keyboard Minus - NKEY_MINUS
Keyboard Period . NKEY_DOT
Keyboard Slash / NKEY_SLASH
Keyboard 0 NKEY_0
Keyboard 1 NKEY_1
Keyboard 2 NKEY_2
Keyboard 3 NKEY_3
Keyboard 4 NKEY_4
Keyboard 5 NKEY_5
Keyboard 6 NKEY_6
Keyboard 7 NKEY_7
Keyboard 8 NKEY_8
Keyboard 9 NKEY_9
Keyboard Colon : NKEY_COLON
Keyboard Semicolon ; NKEY_SEMICOLON
Keyboard Equals = NKEY_CIRCUMFLEX
Keyboard At @ NKEY_ATMARK
Keyboard Left Bracket [ NKEY_LEFTSBRACKET
Keyboard Backslash \ NKEY_YEN
Keyboard Right Bracket ] NKEY_RIGHTSBRACKET
Keyboard Caret ^ NKEY_CIRCUMFLEX
Keyboard Underscore _ NKEY_UNDERSCORE
Keyboard Backquote ` NKEY_ATMARK
Keyboard a NKEY_A
Keyboard b NKEY_B
Keyboard c NKEY_C
Keyboard d NKEY_D
Keyboard e NKEY_E
Keyboard f NKEY_F
Keyboard g NKEY_G
Keyboard h NKEY_H
Keyboard i NKEY_I
Keyboard j NKEY_J
Keyboard k NKEY_K
Keyboard l NKEY_L
Keyboard m NKEY_M
Keyboard n NKEY_N
Keyboard o NKEY_O
Keyboard p NKEY_P
Keyboard q NKEY_Q
Keyboard r NKEY_R
Keyboard s NKEY_S
Keyboard t NKEY_T
Keyboard u NKEY_U
Keyboard v NKEY_V
Keyboard w NKEY_W
Keyboard x NKEY_X
Keyboard y NKEY_Q
Keyboard z NKEY_Z
Keyboard Delete NKEY_DEL
Keyboard Keypad 0 NKEY_KP_0
Keyboard Keypad 1 NKEY_KP_1
Keyboard Keypad 2 NKEY_KP_2
Keyboard Keypad 3 NKEY_KP_2
Keyboard Keypad 4 NKEY_KP_4
Keyboard Keypad 5 NKEY_KP_5
Keyboard Keypad 6 NKEY_KP_6
Keyboard Keypad 7 NKEY_KP_7
Keyboard Keypad 8 NKEY_KP_8
Keyboard Keypad 9 NKEY_KP_9
Keyboard Keypad Period . NKEY_KP_DOT
Keyboard Keypad Divide / NKEY_KP_SLASH
Keyboard Keypad Multiply * NKEY_KP_ASTERISK
Keyboard Keypad Minus - NKEY_KP_MINUS
Keyboard Keypad Plus + NKEY_KP_PLUS
Keyboard Keypad Enter NKEY_RETURN
Keyboard Keypad Equals = NKEY_KP_EQUAL
Keyboard Up NKEY_UP
Keyboard Down NKEY_DOWN
Keyboard Right NKEY_RIGHT
Keyboard Left NKEY_LEFT
Keyboard Insert NKEY_INS
Keyboard Home NKEY_HOMECLR
Keyboard End NKEY_HELP
Keyboard Page Up NKEY_ROLLUP
Keyboard Page Down NKEY_ROLLDOWN
Keyboard F1 NKEY_F1
Keyboard F2 NKEY_F2
Keyboard F3 NKEY_F3
Keyboard F4 NKEY_F4
Keyboard F5 NKEY_F5
Keyboard F6 NKEY_F6
Keyboard F7 NKEY_F7
Keyboard F8 NKEY_F8
Keyboard F9 NKEY_F9
Keyboard F10 NKEY_F10
Keyboard F11 Mouse capture (hidden/show toggle)
Keyboard F12 NP2 menu key
Keyboard Caps Lock NKEY_CAPS
Keyboard Right Shift NKEY_SHIFT
Keyboard Left Shift NKEY_SHIFT
Keyboard Right Control NKEY_CTRL
Keyboard Left Control NKEY_CTRL
Keyboard Right Alt NKEY_KANA
Keyboard Left Alt NKEY_KANA
Keyboard Print NKEY_COPY

Supported combinations

  • If you use 104 western keyboard, to input underscore(_), press Shift+right Ctrl.


RetroMouse Inputs NP2 Mouse Inputs
Mouse Cursor Mouse Cursor
Mouse 1 Mouse Left Button
Mouse 2 Mouse Right Button
Mouse 3 NP2 menu key


Awaiting description.

Last update: 2024-05-17