Niantic has announced that Limited Time Challenge codes will be available at Pokémon GO official partners in Japan. Players are required to purchase items at these partners in order to obtain a code.

Pokémon GO Partner Research

Trainers,
Pokémon GO Partner Research will be held through Pokémon GO official partners, who always support trainers. Participating partners in the first Pokémon GO Partner Research for the Alola season are: Akindo Sushiro, Tully's Coffee, and Yoshinoya.

What is "Pokémon GO Partner Research"?
This is a limited time challenge open only to those who have an entry ticket with a promotion code that can be obtained from official Pokémon GO partners. Different partners will participate each season. The Participation Ticket has a promotion code attached to it, and you will be able to activate the Time Challenge by registering the code on the promotion code entry page. If you complete the Time Challenge during the applicable season, you will receive items and Pokémon!

How to obtain participation tickets
Availability period and method of acquisition differs for each partner. Please check the Partner Campaign page for details.

• Akindo Sushiro
  Period: Starting April 7th, 2022 - *Each store will close as soon as all the food is gone.
  How to get the coupon: Purchase a takeout or delivery item at Sushiro, and one coupon will be attached to each item.
  Campaign page: https://www.akindo-sushiro.co.jp/campaign/detail.php?id=2668
• TULLY'S
  Period: Monday, April 18th, 2022 to Sunday, May 15th, 2022 How to get the ticket: Present the barcode for obtaining the ticket found in the "Tully's Official App" before paying at a Tully's Coffee store, and purchase more than 700 yen per account including tax with a registered Tully's card in the "Tully's Official App" to obtain the ticket.
  Campaign page: https://www.tullys.co.jp/cpn/pokemon_2022/
• Yoshinoya
  Period: April 25th, 2022 11:00 to May 31st, 2022 at 20:00
  How to get the ticket: Spend 550 yen or more per account including tax at a Yoshinoya restaurant and present the barcode in the "Yoshinoya App" to get the ticket.
  Campaign page: To be released at a later date

Limited Time Challenge Contents

Clear deadline: From code registration to 23:59 Japan time on May 31st, 2022
If you complete the Limited Time Challenge, you will receive items and Pokémon. Plus, you get 10,000 XP and 10,000 Stardust for clearing to the end!

For each partner, the Pokémon you can get is different. If you're lucky, you may even see some alternate-colored Pokémon! (You cannot find alternate-colored Mokuroh, Nyabby, and Ashimari.)

• Sushiro: Nyabby, Patcheel, Garagara (Alola Form), Iwanko
• Tully's: Mokuroh, Beroringa, Betbeton (Alola Form), Iwanko
• Yoshinoya: Ashimari, Tabunne, Raichu (Alola Form), Iwanko
• Research task, items and XP to be obtained are the same for all partners.
• Only one time challenge can be attempted per partner. However, you can can obtain a participation ticket from each partner and challenge each limited time challenge.

What happens after I get my "Pokémon GO Partner Research" participation ticket?
Once you have received your ticket, please enter the promotion code on the ticket at the promotion code entry page. Once the code is registered, the limited time challenge will appear in the "Today's Summary" tab in the game.

Please be aware of your surroundings and follow guidelines from local health authorities when playing Pokémon GO. Upcoming events are subject to change.

Source: https://pokemongolive.com/ja/post/202203partnerresearch-jp/