Biisan wa Naze Naku Naru no ka?

**Biisan wa Naze Naku Naru no ka?** (ビーサンはなぜなくなるのか？; *Why are the Beach Sandals Gone?*) is LAPIS ARCH's 29th single. It was released on June 22, 2022.

## Tracklist

1. Biisan wa Naze Naku Naru no ka? / Senbatsu (Akagumi ver.)
2. Biisan wa Naze Naku Naru no ka? / Senbatsu (Shirogumi ver.)
3. Soko Made Aruite Iku yo (そこまで歩いていくよ; *I'll Walk There*) / Ito Momoka
	* (Type-A) Himawari no Suisaiga (向日葵の水彩画; *Sunflower Watercolor Painting*)
	* (Type-B) Juubun, Shiawase (充分、しあわせ; *Happy Enough*) / Undergirls
	* (Type-C) Kanashimi no Jouka Souchi (悲しみの浄化装置; *Sadness Purification Device*) / Kenkyuusei
	* (Type-D) Aruite Ikou (歩いていこう; *Let's Go On*) / Hirokawa Nanase, Tanabe Ririka, Toyoshima Cocoro
4. Biisan wa Naze Naku Naru no ka? (off-vocal)
5. Soko Made Aruite Iku yo (off-vocal)
	* (Type-A) Himawari no Suisaiga (off-vocal)
	* (Type-B) Juubun, Shiawase (off-vocal)
	* (Type-C) Kanashimi no Jouka Souchi (off-vocal)
	* (Type-D) Aruite Ikou (off-vocal)

## Regular Edition Details

CD
1. Biisan wa Naze Naku Naru no ka? / Senbatsu (Akagumi ver.)
2. Biisan wa Naze Naku Naru no ka? / Senbatsu (Shirogumi ver.)
3. Soko Made Aruite Iku yo
4. Kaeritakunatta yo (帰りたくなったよ; *I Wanted to Go Home*)
5. Biisan wa Naze Naku Naru no ka? (off-vocal)
6. Soko Made Aruite Iku yo (off-vocal)
7. Kaeritakunatta yo (off-vocal)

## Included Members

### **"Biisan wa Naze Naku Naru no ka?"**

**★ Senbatsu** (Akagumi ver.) (21 Members) (Ito Momoka Center)

* **1st Generation**: Kato Yuuka, **Ito Momoka**, Omori Miyuu, Uemura Akari, Oda Sakura, Kamikokuryo Moe
* **2nd Generation**: Uemura Rina, Miyata Manamo, Ishida Yuumi, Taniguchi Megu, Shimoguchi Hinana
* **3rd Generation**: Yamashita Emiri, Fukuda Akari, Hirokawa Nanase, Yamauchi Yuna, Mukai Hazuki, Tanimoto Ami, Kaga Kaede, Kishimoto Yumeno, Noguchi Iori, Yoda Yuki

### **"Biisan wa Naze Naku Naru no ka?"**

**★ Senbatsu** (Shirogumi ver.) (21 Members) (Yabuki Nako Center)

* **3rd Generation**: Kobayashi Kaho, Jonishi Rei, **Yabuki Nako**, Tanaka Miku
* **4th Generation**: Kurosu Haruka, Kawata Hina, Yamauchi Mizuki, Ishida Chiho, Kawatoko Asuka, Iwata Hina, Tanabe Ririka
* **5th Generation**: Matsuda Rina, Satoyoshi Utano, Kiyohara Kaya, Kakehashi Sayaka, Toyoshima Cocoro, Kawabata Yume
* **6th Generation**: Ozono Rei, Manabe Anju, Kawamata Anna, Hirasawa Haruka

### **"Soko Made Aruite Iku yo"**

Ito Momoka's graduation song

(1 Member)

* **1st Generation**: Ito Momoka

### **"Himawari no Suisaiga"**

(17 Members) (Kiyohara Kaya Center)

* **1st Generation**: Omori Miyuu, Kamikokuryo Moe
* **2nd Generation**: Uemura Rina, Miyata Manamo, Shimoguchi Hinana
* **3rd Generation**: Yamashita Emiri, Fukuda Akari, Kobayashi Kaho
* **4th Generation**: Kawata Hina, Kawatoko Asuka, Iwata Hina
* **5th Generation**: Matsuda Rina, Satoyoshi Utano, **Kiyohara Kaya**, Kakehashi Sayaka
* **6th Generation**: Manabe Anju, Kawamata Anna

### **"Juubun, Shiawase"**

Undergirls (13 Members) (Ise Layla Center)

* **4th Generation**: Shimakura Rika, Ono Mizuho, Yokoyama Reina
* **5th Generation**: Fujimoto Fuyuka, Iriuchijima Sayaka, Abe Wakana, Akiyama Mao, **Ise Layla**
* **6th Generation**: Nagata Shiori, Sakurai Momo, Fukuda Marine, Harada Toa, Okamura Homare

### **"Kanashimi no Jouka Souchi"**

Kenkyuusei (14 Members) (Esumi Renon Center)

* **Kenkyuusei**: Mogami Nanaka, Hara Yune, Ikeda Teresa, Mizushima Miyuu, Yamazaki Sora, Ui Yurari, **Esumi Renon**, Sakata Misaki, Hashimoto Eriko, Hirayama Yuki, Yamamura Sakura, Takahira Yuna, Kawamura Kokoa, Yoshino Misaki

### **"Aruite Ikou"**

Hirokawa Nanase, Tanabe Ririka and Toyoshima Cocoro's graduation song

(3 Members)

* **3rd Generation**: Hirokawa Nanase
* **4th Generation**: Tanabe Ririka
* **5th Generation**: Toyoshima Cocoro

### **"Kaeritakunatta yo"**

(5 Members)

* **2nd Generation**: Shimoguchi Hinana
* **3rd Generation**: Kobayashi Kaho
* **4th Generation**: Ishida Chiho
* **5th Generation**: Ise Layla
* **6th Generation**: Fukuda Marine

## Trivia

* First senbatsu of Kurosu Haruka, Toyoshima Cocoro and Manabe Anju.
* First single to feature 7th Generation members.
* Last senbatsu and single of Ito Momoka, Hirokawa Nanase, Tanabe Ririka and Toyoshima Cocoro.