The title of the puzzle is the first line of the famous Japanese poem, Iroha. It contains all but one kana, or syllabic Japanese script, once; for this reason, it is frequently used as an ordering of kana before the Gojūon ordering system became popular. The Gojūon (literally, "50 sounds") is a table of the Japanese syllables, roughly indexed by transliteration sound, i.e., the 10 row indices are consonant sounds, and 5 column indices are vowel sounds.
Here is Iroha written in hiragana, one of the three kana:
Here is the Gojūon written in hiragana (image courtesy of en.wikipedia.org):
While reading about the Gojūon, one notices the chart is 10 rows by 5 columns, oddly similar to the given chart of letters. Overlaying the Gojūon on the chart gives a mapping between kana and letters. Then one sequentially indexes the 47 hiragana from the poem into the chart to get the string
PLURALOFWORDTHATFOLLOWSSHRINKGIFTSANDWICHORBODY, whose answer is