"Kitten-sized" rats appear in the city—what is happening in Kabukicho?

2) Why Have They Increased? — Post-COVID Human Flow Return and "Urban Structure"

According to the ward's interviews, the main causes of the rat increase are broadly two.

• (A) Increase in Garbage and Poor Management: With the recovery of human flow, nighttime food waste has increased, and the disorder in bag disposal, collection timing, and storage environment becomes an attraction (food for rats).

• (B) Building Deterioration and Gaps: Old multi-tenant buildings, dense back alleys, and complex piping easily become "hideouts" and "passages."
  
  
  These are common issues in the downtown areas of New York, Hong Kong, and London. Kabukichō can be said to be a district where the "four conditions for rat breeding" — high density, nighttime economy, frequent garbage, and old architecture — are likely to overlap.Toyo Keizai Online

3) Shinjuku Ward's Measures: Not Just 200 Poisoned Bait Placements

Reports highlight the placement of poisoned bait at about 200 locations, but that's not all there is to the operations. Generally, a municipality's full-scale measures involve

1. Survey (understanding nesting and pathways)

2. Environmental Improvement (cutting off garbage, water, and gaps)

3. Extermination (poisoned bait, traps)

4. Monitoring (patrols and evaluations to prevent recurrence)
   
   
   cycle. Shinjuku Ward also operates with a design that combines **"environmental survey + area-wide extermination + sequential evaluation,"** showing a stance that does not rely solely on "extermination." According to the ward's explanation at the time in 2023, the supplementary budget included costs for environmental surveys and new business expenses.Nikkan Gendai DIGITAL

4) Is "Kitten Size" an Exaggeration? — The Gap Between Perception and Biology

"Kitten size" is a buzzworthy expression even in overseas articles (Kabukichō has long been a site for rats… kitten-size rats). However, the adult brown rat, common in cities, appears large when including the tail, and in "dim environments + surprise," it is easy to feel perceptually larger. Photos and videos from the field amplify the "strength of perception," but a calm evaluation considering individual differences and shooting conditions is necessary.Unseen Japan

5) Practical Advice for Travelers (To Enjoy the Nightlife)

① Avoid Areas Around Street Garbage: Smells and food scraps are the strongest "lures." Do not approach or stop.
② Light Foot Attention: Rats run when startled by human shadows. Especially if wearing sandals.
③ Choosing Restaurants: Check the cleanliness of the exterior and entrance, the state of garbage storage, and the tidiness around the kitchen.
④ Night Photography: Do not narrow your field of vision by focusing too much on alley photography.
⑤ If Bitten or Scratched: Quickly proceed to wash with running water + disinfect + visit a medical institution. Check tetanus vaccine history just in case.
(Note: This is general advice and not a substitute for medical advice.)

6) For Store and Building Owners: A Minimum "To-Do List"

• Garbage Should Be "Sealed and Short-Stayed": Minimize the time difference to the collection site. Use double bags and lidded containers.

• Seal Building Gaps: Seal pipe and wall holes, and door gaps with metal mesh and sealing.

• Cut Off Outdoor Water and Oil: Frequently clean drains, grease traps, and outdoor oil stains.

• Monitoring: Use black rat tracking powder and snap traps to "visualize" pathways.

• Work with Specialists and PDCA: Instead of one-time extermination, plan annually according to seasons and events.

7) It's Not "Only in Japan": The Reality of Global Cities

In recent years, food hygiene incidents have also attracted attention, and in March 2025, Japan's largest beef bowl chain temporarily closed about 2,000 stores in response to "risks of rat and insect contamination." The urban dining industry is being challenged by both the transparency of the video era and hygiene standards.The Japan Times

Meanwhile, Singapore has strengthened strict enforcement of violations (penalties increased from April 2025), and in the UK, local governments spent over £40 million on rat control in 2024 alone. The global trend is moving towards shifting **"mass outbreaks → complaints → extermination"** from a cycle to one where responsibility and cost are managed by the "emitters (stores and buildings)."nea.gov.sg+1

8) What "Worked" and "Didn't Work" in Kabukichō?

Worked:

• Comprehensive placement of poisoned bait (about 200 locations) + survey set operation

• Publicity and Awareness (posters and on-site guidance)
  
  
  Less Effective:

• Cases where "holes" in individual buildings are left unaddressed

• Overnight garbage retention (collection cycles/placement are inconsistent)

• One-time extermination (rebound due to re-entry from surrounding areas)

These are "common issues" seen in downtown areas worldwide and are not unique to Japan. Addressing weaknesses with both **"the structure of the district" and "human behavior"** is a realistic solution with high cost-effectiveness.Toyo Keizai Online

9) Three Lessons for Tourist City Tokyo

1. Data Infrastructure: At the ward level, mapping of occurrence situations and visualization of seasonal variations (report data, cleaning company logs, SNS detection, etc.).

2. Regulation × Incentives: Penalties for malicious cases, recognition and visibility for exemplary stores.

3. Hygiene UX of the "Night Economy": Optimize nighttime garbage collection schedules, smart locks and surveillance for shared collection points, multilingual advisories at tourist information centers.

10) For Travelers' Peace of Mind — Final Checklist

• "Walking First" in Night Alleys (Feet → Photography in order)

• 70% Can Be Judged by the "Exterior" of Restaurants (Garbage, drainage, around the kitchen)

• Contact Information in Case of Trouble: Hotel, travel insurance, nearest clinic

• With Children: Avoid proximity to garbage sites and building backs

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