It looked identical to the sword seen in an anime called Rurouni Kenshin by the character Sword Hunter Cho. But this one was not a cosplay item.
I need more info about this sword & the real Japanese name Please.
It looks like this: http://users.skynet.be/aoshihomepage/Kenshin/Weapons/Renbatto.jpg It is a real sword though, not just a manga one 
♡I hesitated to answer because I've never personally seen a double blade sword here in Japan... BUT! It sounds a lot like the Fantasy double blade sword.
Take a look here:
hand forged red japanese katana flower tsuba sword sharpened can cut tatami, battle ready japanese samurai katana tiger tsuba katana sword white sheath sharp, handmade japanese samurai katana demon tsuba titanium adsorb folded steel sword, Clay tempered t-10 blade katana plum blossom tsuba sword, hand forged red japanese bamboo tsuba katana sword sharpened can cut tatami , hand forged red japanese skull tsuba katana sword sharpened can cut tatami , hand forged japanese tiger tsuba katana sword sharpened can cut tatami, Dragon Tsuba Japanese Samurai Katana Sword Full Tang Carbon Steel Sharp Blade , Hand Forge Japanese Samurai Katana Sword Dragon Tsuba Full Tang Blade Sharp, 40.6"Sharp Handmade Japanese Samurai Katana Sword Gold Dragon Tsuba, SHARP WHITE Chrysanthemum TSUBA JAPANESE KATANA SWORD CAN CUTBAMBOO, Rare Weapon collection Japanese Katana Sword Tsuba Carving Pattern 10937, Dragon Tsuba Yellow Saya Carbon Steel Japana Katana Sword, 0510/08 HANDAMADE JAPANESE DAMASCUS STEEL TSUBA/ FOR SWORD/KATANA , A Dragon Habaki For Japanese Sword Katana -- Tsuba Fuchi Kashira Tsuka Menuki, Dragonfly Fuchi & Kashira For Japanese Katana Sword Tsuka -- Menuki Tsuba Habaki, A Dragon Tsuba For Japanese Sword Katana -- Tsuka Menuki Habaki Fuchi Menuki, A Koi-Fish Habaki For Japanese Sword Katana -- Tsuba Fuchi Kashira Tsuka Menuki , A Sanskrit Habaki For Japanese Katana --- Tsuka Kashira Fuchi Menuki Tsuba Sword, Full hand Iron tsuba practical clay tempered japanese samurai katana sword JP07, HANDMADE IRON SNAKE MONKEY TSUBA FOR JAPANESE SAMURAI SWORD KATANA, Japanese Sword Book Vintage Weapon Katana Tsuba Tanto, Musashi Black Tsuba Guard for Japanese Samurai Warrior Katana Wakizashi Sword, full hand practical Iron tsuba clay tempered japanese samurai katana sword #JP08, Handmade Japanese Samurai Katana Sword Cyclone Tsuba Full Tang Blade Sharp, JAPANESE SAMURAI SWORD KATANA AISI 1060 Steel Full Tang Blade Dragon&Snake Tsuba, Handmade Razor Sharp Japanese Sword Skull Tsuba Katana FULL CUSTOMIZATION & Bag, 1060 High Carbon Steel FullTang Blade Locust Tsuba Japanese Samurai Sword Katana, 40.6"Phenix Tsuba 1060 Carbon Steel Japanese Samurai Sword Katana Fulltang blade, ROUND TSUBA RED SAYA VINTAGE HANDMADE JAPANESE SWORD KATANA,
