IZUMOYA SUMIHACHI (SUMI8)
Let's change the air. Charcoal that quietly works on humidity and odor.
Born in humid Izumo, "SUMI8" is a humidity-control charcoal made and sold by Izumo Carbon. Developed together with Izumo Doken, it has been on the market since 2002. It comes as a bag you simply place where moisture builds up — under the floor, in a room, or inside storage. The charcoal is mainly made from softwood, with efforts to reuse quality wood such as demolition timber and wooden pallets. No batteries. No refills. Just long-lasting moisture control and odor adsorption. From the classic 12L size to 3L, mini sticks, and slim small packs, you can pick by space.
Why We Love It
Start small: put the slim pack in drawers or storage boxes where air tends to stagnate. Next, try the 3L size in a closet or car for compact moisture-prone spots. During the rainy season, place a 12L bag in a room corner or under the bed. If you're building or renovating, consider the underfloor type at the same time. A monthly sun-dry routine keeps it feeling like a reliable everyday tool.
PROFILE About the Company / Workshop
SUMI8 is a humidity-control charcoal made and sold by Izumo Carbon in Izumo, Shimane. Built around the absorb-and-release mechanism, it is positioned as Japan's only "humidity-control charcoal." Developed together with Izumo Doken, sales began in 2002. The concept is simple: place it where dampness tends to gather — under the floor, in rooms, or inside storage.
Inside are charcoal chips made mainly from softwood (pine, cedar, cypress, etc.), with efforts to reuse quality wood such as demolition timber and wooden pallets. The bag structure differs by use (single or double layers). You keep it in the bag, reducing dust concerns. It absorbs humidity when it rises and releases it when it drops, while also adsorbing unpleasant odors — no batteries, no refills.
The lineup is space-first. Underfloor types (12L, 45cm square) are placed across the crawl space. Indoor 12L bags suit rooms, closets, and under beds. There are also 8L for closets, 3L (35×28cm), mini sticks (8×21cm, 2-pack), and slim small packs (19cm square, 0.4L). A size chart makes selection straightforward.
Usage stays simple: place it in the bag. For indoor types, sun-drying about once a month is suggested for comfortable upkeep. Underfloor types are described as usable semi-permanently after installation. Purchase options are organized in retailer lists, including routes to Rakuten shops. Support is available by phone (weekdays 8:30–12:00, 13:00–17:00) and via email form.
A humidity-control idea born from Izumo's damp climate
SUMI8 was created in Izumo to tackle moisture-related issues. As Japan's only "humidity-control charcoal," it absorbs excess humidity and releases it when the air dries. Izumo Carbon manufactures and sells it, and the product has supported moisture control choices since its 2002 launch.
Softwood charcoal, designed to be used in the bag
The core is softwood charcoal chips. The brand also reuses quality wood such as demolition timber and wooden pallets. Packed in non-woven polypropylene bags (indoor types use double layers), it's made to be placed as-is — clean and easy for drawers, boxes, and bags.
Over 2× Binchotan humidity control, plus odor adsorption
The indoor series claims more than double the humidity-control power of Binchotan. It works without batteries and can be used semi-permanently, removing excess moisture and adsorbing unpleasant odors. The 12L cushion-like bag fits neatly in corners, closets, or under beds.
Pick by space: from underfloor to small boxes
There are clear sizes for clear places: 12L for underfloor and indoor use, 8L for closets, 3L for compact spots, mini sticks for shoes and bags, and slim small packs (0.4L) for drawers and storage cases. Start with where you want to place it.
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SUMI8 Indoor (12L)
A classic size for rooms, closets, and under-bed use. 12L capacity in a 45cm-square, cushion-like bag. Use it as-is in the bag.
SUMI8 (3L)
An easy-to-handle size for closets, under-sink areas, and cars. 3L capacity, sized 35×28×5cm.
SUMI8 Mini (2-pack)
Mini sticks for tight spaces like shoes and bags. 8×21×3cm, 0.2L each (2 pieces).
SUMI8 Slim Small Pack (0.4L)
A slim option for drawers, storage cases, and small boxes. 19×19×2.5cm, 0.4L capacity.