diff --git a/src/mame/mame.lst b/src/mame/mame.lst
index 09d8bafcd97a5..9b0960ee8fab2 100644
--- a/src/mame/mame.lst
+++ b/src/mame/mame.lst
@@ -44030,6 +44030,7 @@ shine
 
 @source:skeleton/shoken_md06.cpp
 petitlot
+polarstar2
 
 @source:skeleton/si5500.cpp
 si5500
diff --git a/src/mame/skeleton/shoken_md06.cpp b/src/mame/skeleton/shoken_md06.cpp
index 6dbd5e25b0aa0..8d2b3599a2e1f 100644
--- a/src/mame/skeleton/shoken_md06.cpp
+++ b/src/mame/skeleton/shoken_md06.cpp
@@ -18,6 +18,13 @@ push-button (reset?)
 unpopulates spaces marked for MSM9810B and ROM
 
 DIP sheets are available
+
+ポーラスター2 (Polar Star 2) by Showa Giken (Shoken)
+'MB-01 MAIN-B' PCB:
+KL5C80A12CFP CPU
+RTC62423 RTC
+push-button (reset?)
+16.00000 MHz XTAL
 */
 
 
@@ -25,6 +32,7 @@ DIP sheets are available
 
 #include "cpu/z80/kl5c80a12.h"
 #include "machine/msm6242.h"
+#include "sound/okim9810.h"
 
 #include "emupal.h"
 #include "screen.h"
@@ -42,27 +50,39 @@ class shoken_md06_state : public driver_device
 	{ }
 
 	void petitlot(machine_config &config) ATTR_COLD;
+	void polarstar(machine_config &config) ATTR_COLD;
 
 private:
 	required_device<kl5c80a12_device> m_maincpu;
 
 	void program_map(address_map &map) ATTR_COLD;
 	void io_map(address_map &map) ATTR_COLD;
+	void sound_io_map(address_map &map) ATTR_COLD;
 };
 
 
 void shoken_md06_state::program_map(address_map &map)
 {
-	map(0x00000, 0x04fff).rom();
+	map(0x00000, 0x08fff).rom();
+	map(0x09000, 0x0cfff).ram();
 	map(0xe0000, 0xe3fff).ram();
+	map(0xfcc00, 0xfffff).ram();
 }
 
 void shoken_md06_state::io_map(address_map &map)
 {
 	map.global_mask(0xff);
-	map.unmap_value_high();
+	map(0x40, 0x40).nopw();
+	map(0x80, 0x80).noprw();
 }
 
+void shoken_md06_state::sound_io_map(address_map &map)
+{
+	map.global_mask(0xff);
+	map(0x3b, 0x3b).rw("oki", FUNC(okim9810_device::read), FUNC(okim9810_device::write));
+	map(0x40, 0x40).nopw();
+	map(0x80, 0x80).noprw();
+}
 
 static INPUT_PORTS_START( petitlot )
 	PORT_START("IN0")
@@ -129,6 +149,28 @@ static INPUT_PORTS_START( petitlot )
 	// TODO: 5 10-position rotary switches
 INPUT_PORTS_END
 
+static INPUT_PORTS_START( polarstar )
+	PORT_START("IN0")
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_UNKNOWN )
+
+	PORT_START("IN1")
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_UNKNOWN )
+	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_UNKNOWN )
+INPUT_PORTS_END
+
 
 void shoken_md06_state::petitlot(machine_config &config)
 {
@@ -138,20 +180,34 @@ void shoken_md06_state::petitlot(machine_config &config)
 	m_maincpu->set_addrmap(AS_IO, &shoken_md06_state::io_map);
 
 	RTC62423(config, "rtc", 0);
+}
+
+void shoken_md06_state::polarstar(machine_config &config)
+{
+	petitlot(config);
+	m_maincpu->set_addrmap(AS_IO, &shoken_md06_state::sound_io_map);
 
 	// sound hardware
 	SPEAKER(config, "mono").front_center();
 
-	// TODO: sound related ICs aren't present?
+	okim9810_device &oki(OKIM9810(config, "oki", 16_MHz_XTAL / 12));
+	oki.add_route(ALL_OUTPUTS, "mono", 1.0); //divider guessed
 }
 
-
 ROM_START( petitlot )
 	ROM_REGION( 0x10000, "maincpu", 0 )
-	ROM_LOAD( "md06_ver4_1.ic6", 0x00000, 0x10000, CRC(ebc81f10) SHA1(28ac52aeadfbf792da95c01b16fb88f7a5eb1d4e) ) // 1xxxxxxxxxxxxxxx = 0xFF
+	ROM_LOAD( "md06_ver4_1.ic6", 0x00000, 0x10000, CRC(ebc81f10) SHA1(28ac52aeadfbf792da95c01b16fb88f7a5eb1d4e) ) // 1xxxxxxxxxxxxxxx = 0xff
 ROM_END
 
-} // anonymous namespace
+ROM_START( polarstar2 )
+	ROM_REGION( 0x20000, "maincpu", 0 )
+	ROM_LOAD( "polarstar2_mk04_ver.4.5.ic8", 0x00000, 0x20000, CRC(13a7b9dc) SHA1(64aa5591aa676cbb9e00327ac62209b6854c4416) )
+
+	ROM_REGION( 0x100000, "oki", 0 )
+	ROM_LOAD( "polarstar_mb01_sound-b.ic35", 0x00000, 0x100000, CRC(606ae52c) SHA1(6a60f4b1c6ac893cafa373c8af7d2c826304f152) )
+ROM_END
 
+} // anonymous namespace
 
-GAME( 2001, petitlot, 0, petitlot, petitlot, shoken_md06_state, empty_init, ROT0, "Shoken", "Petit Lot (ver. 4.1)", MACHINE_NO_SOUND | MACHINE_NOT_WORKING | MACHINE_MECHANICAL )
+GAME( 2001, petitlot,   0, petitlot,  petitlot,  shoken_md06_state, empty_init, ROT0, "Shoken", "Petit Lot (ver. 4.1)",    MACHINE_NO_SOUND | MACHINE_NOT_WORKING | MACHINE_MECHANICAL )
+GAME( 2004, polarstar2, 0, polarstar, polarstar, shoken_md06_state, empty_init, ROT0, "Shoken", "Polar Star 2 (ver. 4.5)", MACHINE_NO_SOUND | MACHINE_NOT_WORKING | MACHINE_MECHANICAL )