The Nintendo 3DS sold through the manufacturer's entire allotment of 400,000 units in its launch week at the end of February in Japan, but sales have rapidly tapered off and it is now lagging behind the PSP.

According to data released by Media Create, Japanese sales of Nintendo's new glasses-free 3D handheld between 28th March through 3rd April fell to 42,979 units from 50,710 the previous week.

Meanwhile, sales of Sony's PSP increased by nearly 7,000 units to 57,379 from 50,479 the previous week.

Japanese gaming blog Andriasang reports that the 3DS is no longer supply constrained either, and is already being discounted by retailers including Amazon. On the other hand, the PSP continues to sell out in Japan.

The figures will be disappointing for Nintendo, but not entirely unsurprising considering the lack of compelling launch titles. The system may get a second wind when popular franchises like Mario Kart and The Legend of Zelda hit later in the year.

Full charts below (previous week sales in parentheses):

Japan Hardware Sales, 28 March to 3 April

1. PSP: 57,379 (50,479)
2. 3DS: 42,979 (50,710)
3. PS3: 27,453 (28,973)
4. Wii: 10,249 (11,808)
5. DSi LL: 9,706 (9,760)
6. DSi: 9,566 (8,604)
7. PS2: 1,996 (1,862)
8. X360: 1,789 (1,963)
9. PSP go: 696 (616)
10. DS Lite: 629 (730)

Japan Software Sales, 28 March to 3 April

01. NDS: Dragon Quest Monsters Joker 2 Professional (Square Enix, 3/31): 163,008
02. PSP: Ebikore+ Amagami (Kadokawa Games, 3/31): 69,221
03. PSP: Final Fantasy IV Complete Collection (Square Enix, 3/24): 31,382 (135,554)
04. PS3: Dynasty Warriors 7 (Tecmo Koei, 3/10): 26,493 (383,606)
05. PSP: BlazBlue Continuum Shift II (Arc System Works, 3/31): 23,808
06. PS2: Ebikore+ Amagami (Kadokawa Games, 3/31): 17,261
07. PSP: Monster Hunter Portable 3rd (Capcom, 12/1/2010): 15,864 (4,417,517)
08. PSP: Dissidia Duodecim Final Fantasy (Square Enix, 3/3): 15,223 (419,135)
09. 3DS: Pro Baseball Famisuta 2011 (Namco Bandai, 3/31): 12,851
10. PSP: Phantasy Star Portable 2 Infinity (Sega, 2/24): 12,002 (312,419)
11. 3DS: Nintendogs + Cats (Nintendo, 2/26): 10,780 (171,522)
12. PS3: Crysis 2 (Electronic Arts, 4/1): 10,416
13. 3DS: Professor Layton and the Miracle Mask (Level-5, 2/26): 10,304 (252,953)
14. NDS: Pokemon Black & White (Pokemon, 9/18/2010): 9,306 (5,136,984)
15. 3DS: Naruto Shippuuden Shinobi Rittai Emaki (Takara Tomy, 3/31): 8,127
16. WII: Wii Party (Nintendo, 7/8/2010): 7,998 (1,837,933)
17. PSP: SD Gundam G Generation World (Namco Bandai, 2/24): 7,900 (291,702)
18. PS3: Way of the Samurai 4 (Spike, 3/3): 6,596 (117,079)
19. PSP: Fairy Tail Portable Guild 2 (Konami, 3/10): 6,571 (38,015)
20. 3DS: Gundam The 3D Battle (Namco Bandai, 3/24): 6,521 (30,021)