This is the original image used for an advertising poster in the early Showa period, circa 1934 or '35. It was drawn by Tomitaka Matsuda, a Japanese-style artist who was also responsible for the front covers of the ladies' magazine Shufunotomo (Housewife's Companion). Behind the smiling, familiar form of the lady in a kimono are a dozen or more of the brown 1-sho sake bottles Gekkeikan was putting its efforts into selling at the time.
The aroma and color of sake will change when exposed to light. The ultraviolet rays degrade the sake ingredients, causing unpleasant smells and affecting the quality negatively. In 1928, it was confirmed by our research institute that brown colored sake bottles were effective in preventing this degradation of sake, as they blocked more ultraviolet light than the blue transparent bottles that were the standard bottle used before then, and so sales of sake in brown 1-sho sake bottles was started properly from that year.
This poster also states that Absolutely no preservatives used, which is advertising the fact that in 1911, Gekkeikan had succeeded in research and developing Japan's first sake that did not need preservatives, and had been popularizing it ever since.