こだま means “echo,” referring to a sound that reverberates and returns. It can also feel poetic or personified, unlike the more everyday word 反響（はんきょう）.
In the song, the names the two people call to each other begin to echo, creating a moving image of their connection lingering through time and distance.
"楓" (kaede, maple) is a goodbye song that refuses to be bitter. It opens with a promise, "忘れはしないよ 時が流れても" (I won't forget, even as time flows), and the things he swears to remember are tiny: the teasing back and forth, and the way "心のトゲさえも君が笑えばもう" (even the thorns in my heart, once you laughed) "小さく丸くなっていたこと" (had turned small and round). That image of a thorn worn smooth by someone's laugh is my favourite thing in the whole song. Then there is the odd, sweet memory of taking turns peeking through a hole, "かわるがわるのぞいた穴から" (through the hole we peeked into by turns) "何を見てたかなぁ?" (what were we looking at?). He can't even remember what they saw. He just remembers doing it together.
The chorus is where it hurts: "さよなら 君の声を抱いて歩いていく" (goodbye, I'll keep walking, holding your voice). He admits some dreams "一人きりじゃ叶えられない" (can't come true on your own), and he wonders "僕のままで どこまで届くだろう" (just as I am, how far can I reach?). Before meeting her he had a "軽いタマシイ" (a light soul) that the wind could blow away, and believed in "他人と同じような幸せ" (the same kind of happiness as everyone else). Watch the little "のに" at the end of that line: it means "even though" or "and yet", so he is quietly saying that belief didn't hold up. Learner tip: "タマシイ" (soul) is normally written 魂, and Spitz spelling it in katakana makes it feel lighter and a bit strange, which suits a soul that floats away. The ending, "聴こえる?" (can you hear me?), is two words and lands harder than any big speech would.
Spitz is a Japanese rock band formed in Tokyo in 1987 by four art school students: Masamune Kusano on vocals and guitar, Tetsuya Miwa on lead guitar, Akihiro Tamura on bass and Tatsuo Sakiyama on drums.
They released their first single, "Hibari no Kokoro", in 1991. The single "Robinson" (1995) sold more than 1.6 million copies, "Cherry" (1996) more than a million, and the 1995 album Hachimitsu topped the Oricon chart and won Best Album at the Japan Record Awards.