It might come as something of a surprise, but in addition to the traditional gift-giving periods of お中元 (o-chūgen, mid-summer) and お歳暮 (o-seibo, year-end — which precedes the Christmas season), the months of March and April are probably the third most popular of Japan's major gift-giving seasons.
Why? For one reason: These two months mark the end and beginning of the academic year, described as 卒業、 新入学 (sotsugyō, shin-nyū gaku, graduation and matriculation), making it the time in which students receive congratulatory gifts.
It makes sense, then, that just prior to March, companies launch sales of new products. During the decade I spent working as an in-house translator at Aiwa （アイワ, an electronics manufacturer recently resurrected in Chicago), I was kept busy turning out translations of press releases, called 新製品情報 (shinseihin jōhō, new product information), which, accompanied by photographs, were mailed out to the media.