The smell of wet hay hits you the moment Yasunori Omiya opens the door to his new home, in Tuen Mun. Sweet and earthy, the scent is one many associate with "old" Japan, where tatami flooring was the preferred surface on which to sleep, eat and receive guests - for those wealthy enough to have a spare room.

The washitsu (Japanese-style room) is one of many reminders of the country to which Omiya will one day return, with his Hong Kong-born wife, Queenie Leung, and their daughter, Ayaka, barely a year old.

"They want her to grow up the traditional Japanese way," says interior designer Samuel Ng, who joined two flats on different floors to create the 1,220 sq ft, five-bedroom duplex.

The upper flat - which the couple bought six months before snapping up downstairs and doubling their living area - contains the sitting and dining areas, the kitchen and two guest rooms. In the bathroom on this level - as in the two downstairs - there is another Japanese cultural export: the all-singing, all dancing bidet toilet with de rigueur warm seat. It even wears a terry cloth seat cover, just as its siblings in Japan might.

Still, Omiya, a businessman who has lived in Hong Kong for 15 years, says he doesn't feel like he's back in Japan when he returns from his nearby office. That's because, despite the Japanese touches, the sea-view duplex otherwise boasts a clean, contemporary Western design complemented by Italian brands such as B&B Italia, Flexform, Artemide and Boffi.

The difficulty in designing the duplex, says Ng, wasn't so much how to marry Japanese and other styles but pulling the two floors together so that guests "don't go upstairs or downstairs and feel as though they're entering a different flat".

One way to achieve this was to use engineered-oak flooring upstairs and down. In addition, the same wallpaper was used to line the corridors on both floors.

Then there's the art that connects the two levels: a tactile map of Japan - with Hokkaido on the ceiling of the top floor and the southernmost main island of Kyushu on the storey below - adds colour to the walls by the staircase connecting the once discrete flats.

More than the map, the use of 10 wallpaper patterns throughout the duplex speaks volumes about who lives within its walls. The Japanese, according to Omiya, love the stuff.

"Wallpaper gives texture and a three-dimensional feeling," says Ng. "Visually, it's more powerful than paint."

That said, the bulk of the wallpaper is muted, save for that on a feature wall in Ayaka's room that explodes with primary hues. The baby, whose room is beside her parents' suite, is being trained to sleep Japanese-style, on a thin mattress on the floor.

The couple's favourite room, perhaps not surprisingly, is their own, and not just because it has a scenic balcony. Sitting beneath the top-floor living room, dining area, kitchen and entrance, it is a generous space, with a walk-in wardrobe and, through it, an en-suite bathroom.

It also has a special feature. Instead of blocking off the original entrance to the lower flat, Ng designed a "ninja door" (see Tried + tested), which allows the couple to enter and leave the flat without having to disturb anyone on the floor above.

It's also in the master bedroom that Ng pandered to the Japanese affinity for sliding doors. He needed no persuading in including them in his design. "They save space and, these days, they are durable and easy to open and close without effort," says Ng. "Big sliding doors are beautiful and sexy."

Dining area The dining area’s walls feature marble- like tiles from Pacific Gallery (159 Lockhart Road, Wai Chai, tel: 2827 9918). Illuminating the table (€4,000/HK$33,760), imported from Flexform (www.flexform.it), in Italy, is a Tom Dixon pendant lamp (HK$4,500) bought at Lane Crawford Home Store (Pacific Place, Admiralty, tel: 2118 2288). The chairs (€4,000 for six) came from B&B Italia (www.bebitalia.com), also in Italy.

Living room Situating the living and dining areas on the top floor was the advice of a fung shui practitioner. The open area is furnished with a Maxalto sofa (€15,000) from B&B Italia and a coffee table and rug bought years ago in Japan. The ceiling lamp (HK$18,000) was from Artemide (Ruttonjee Centre, 11 Duddell Street, Central, tel: 2523 0333). The wallpaper (HK$300 per square metre) came from Tat Ming (16/F, Kwan Chart Tower, 6 Tonnochy Road, Wan Chai, tel: 2893 2337) and the goldfish art was from OVO (various locations; www.ovohome.com.hk).

Staircase One room on each floor was sacrificed to accommodate the staircase. Extending from the ceiling to the bottom step is a map of Japan made of polyurethane soft "tiles", which cost HK$20,000 from Run Sheng Trading Development (9/F, Yip Win Factory Building, 10 Tsun Yip Lane, Kwun Tong, tel: 2357 4608). The sculptures on the window sill were from a shop in HomeSquare, Sha Tin. 

Tatami room The room, used by Yasunori Omiya’s family when they visit Hong Kong, features deep cabinets for storing futon mattresses. The tatami mats (HK$10,000 for the whole room) came from Da Yi Tatami Furniture (2/F, Wing Cheung Industrial Building, 58 Kwai Cheong Road, Kwai Chung, tel: 3171 7661) and the wallpaper (HK$300 per square metre) from Tat Ming. The ceiling light (HK$3,600) came from ELighting (48 Morrison Hill Road, Wan Chai, tel: 2573 7772). The slatted sliding doors are fitted not with traditional rice paper, which is easy to damage, but with plastic sheets from Tat Ming. The plastic cost a total of HK$1,130 and the doors were made for HK$3,000. The cushion is old.

Kitchen The kitchen, enlarged by removing a helper’s room at the back, was fitted with cabinetry imported from Boffi (www.boffi.com), in Italy. The XILA 09 kitchen cost about HK$150,000 plus freight. The gooseneck tap (HK$7,000) came from SL Gallery (Kiu Yin Commercial Building, 361 Lockhart Road, tel: 2598 0298).

Main bedroom Almost a self-contained unit, the main bedroom includes a dressing area with wardrobes providing space for a small fridge and Omiya’s collection of manga. The bed (about HK$48,000) came from Meridiani (www.meridiani.it), in Italy, and the colourful chair (HK$6,000) from a shop in HomeSquare. The bedside tables (€1,500 for two) and small coffee table by the chair came from Flexform. The pouffe and rug came from Japan. The wallpaper (HK$600 per square metre) behind the bed was from Tat Ming. The room can be closed off from the dressing area with a wide sliding door.

Dressing area and main en-suite bathroom Omiya and his wife, Queenie Leung, chose to have the basin unit outside the bathroom so they could enjoy a direct green view out the side window while brushing their teeth. The basin (HK$4,700) came from Colourliving (333 Lockhart Road, tel: 2510 2666). The mosaic tiles on the far wall of the shower came from Pacific Gallery. Engineered oak (HK$108 a square foot) was supplied and installed by Ka Shun Decoration Construction (5/F, 153 Kowloon City Road, To Kwa Wan, tel: 9029 2620).

TRIED + TESTED
Double duty To meet fire-safety regulations, the original entrance to the flat, on the lower floor, was retained. Samuel Ng, of S&B design (10/F, Bonham Centre, 79 Bonham Strand, Sheung Wan, tel: 2866 2288), concealed the door behind a wide sliding one that is part of a set closing off a wardrobe. "The sliding door provides an extra layer of security," says Ng. "We used mirror black stainless steel for the frame, to give it a luxurious yet tough feel." The stainless steel came from Cobelco (21/F, Tung Wai Commercial Building, 109 Gloucester Road, Wan Chai, tel: 2889 0080).