What GRANDSLAM does

GRANDSLAM, operated by 株式会社マスターピース (Masterpiece Inc.), is a coworking and event space business founded in September 2019 and headquartered in Fukushima Ward, Osaka, one minute from JR Fukushima Station. The venue operates 50 coworking seats, three private meeting rooms (GalaxyRoom, Nadaya Leather Room, and Kanaru Tanoshii Heya), and an event space accommodating up to 50 attendees, with no proprietary software platform — the offering is fundamentally physical. Revenue is generated through a mix of ¥1,500 daily drop-in passes, ¥16,500/month memberships, hourly meeting room rentals (¥1,000-3,000/hour), event space rentals starting at ¥27,500 for 2 hours, virtual office services (¥5,500/month for address and registration use), and ancillary creative production. The business is operated by an 8-person team led by founder-representative Yoshinaga Ryo.

The go-to-market is community-led, anchored on a "growth, co-creation, and connection" philosophy. GRANDSLAM drives traffic through frequent hosted events — HR study groups, networking mixers, the SPOTLIGHT business contest with a ¥1.4M prize pool, golf tournaments, B-League basketball outings, and the Family Day/Photo Walk series — listed on Peatix where it crossed 100 hosted events in October 2024. Customer segments span freelancers, independent professionals, small businesses and startups, event organizers, and virtual office subscribers in the Kansai region. Distribution is physical-first (walk-in access, no reservation required for daily passes) supplemented by Instagram, Twitter/X, LINE, and the GRANDSLAM MEDIA content platform launched in August 2024.

Following incorporation in March 2020 and weathering the COVID-19 disruption, GRANDSLAM has methodically expanded scope. Two community crowdfunding campaigns on CAMPFIRE (May 2021, ¥1.41M, 157 supporters) and うぶごえ (August 2023, ¥3M, 197 supporters) raised a combined ¥4.41M. The company relocated to a flagship site directly above JR Fukushima Station in July 2023, then initiated geographic expansion with the GRANDSLAM KOBE kickoff in April 2025, the first GRANDSLAM TOKYO event in June 2025, and an AI Research Division also in April 2025. Sub-brands include GRANDSLAM MEDIA, GRANDSLAM NFT Service, GS TIMES video series, and the GRANDSLAM KIRINJI branch. The company won the Peatix Community Award 2026.

Name

GRANDSLAM

Legal name

株式会社マスターピース

Website

https://grandslam.osaka

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

1–10 employees

Short description

GRANDSLAM, operated by Masterpiece Inc., is a community-oriented coworking and event space business in Osaka, Japan, serving freelancers, small businesses, and event organizers with daily and monthly workspace access, meeting rooms, and event venue rentals.

Ownership category

akta.pro rank

Product category

Coworking & Event Space Services

SIC

Services-Membership Sports & Recreation Clubs (7997)

akta.pro primary industry

Guest Management (Invitations, RSVPs, Seating, Check-in) (HSACAAAJ)

Keywords

• Coworking space rental
• Event venue rental
• Meeting room rental
• Virtual office service
• Community event hosting

Headquarters

HQ city

Osaka

HQ country

Japan

HQ region

Asia

Offices3 records

Markets served

GTM type

B2C

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Infrastructure, Others

Revenue model

1. Coworking Space Rental: Daily drop-in passes (¥1,500), monthly plans (¥16,500), and multi-pass options for frequent users. Also includes virtual office services for business registration and address use.
2. Event Space Rental: Hourly and package-based rental of event space for seminars, networking events, and corporate meetings. Pricing varies by group size and duration, starting from ¥27,500 for 2-hour standard plans.
3. Meeting Room Rental: Hourly rental of private meeting rooms (¥1,000-¥3,000/hour depending on room size). Used for web meetings, client interviews, and small team meetings.
4. Creative Services: Creative production services including photography, writing, design, and website production offered as part of business operations.

Pricing tiers

Go-to-market motion2 records

Distribution channels2 records

Marketing channels6 records

Core offering

GRANDSLAM operates a physical coworking and event space in Osaka's Fukushima Ward, offering 50 coworking seats with daily and monthly plans, an event space for up to 50 attendees, three private meeting rooms, and a virtual office service for business registration. The business is built around a community-event model with frequent hosted activities (HR study groups, networking events, business contests, golf tournaments) and supported by a media platform (GRANDSLAM MEDIA) and an NFT service.

Product overview

GRANDSLAM operates as a unified coworking and event space platform offering four interconnected services: a core Coworking Space with 50 seats and daily/monthly plans, Event Space for up to 50 attendees, Meeting Rooms in three configurations (GalaxyRoom, Leather Room, and Kanaru Tanoshii Heya), and Virtual Office for business registration. The space emphasizes 'Growth, Co-creation, and Connections' (成長・共創・つながり) as its founding concept, positioning itself as an 'evolutionary coworking' venue that combines workspace facilities with community-building events and media content through its GRANDSLAM MEDIA sub-brand. Additional offerings include NFT services and video content series.

Differentiator

Problem solved

Functional benefit

Brands

• GRANDSLAM NFT Service: NFT service launched in September 2023
• GRANDSLAM MEDIA
• GS TIMES
• GRANDSLAM KIRINJI
• GRANDSLAM KOBE
• GRANDSLAM TOKYO
• GRANDSLAM Cafe
• GRANDSLAM Studio
• GRANDSLAM Family Day
• GRANDSLAM Photo Walk

Products and services

• Coworking Space 50-seat day-use coworking space with Wi-Fi, power outlets, complimentary coffee, and free entry/exit. Daily drop-in plan at ¥1,500 (no reservation required, unlimited usage) and monthly plans at ¥16,500. Located one minute from JR Fukushima Station on the Osaka Loop Line. Targets freelancers, remote workers, and small teams.
• Event Space Event venue accommodating up to 50 attendees with audio-visual equipment, flexible layouts, and catering options. Multiple rental plans starting at ¥27,500 for 2 hours (standard plan, up to 19 people), ¥33,000 after 5pm on weekdays, group rate of ¥1,430 per attendee for 20+ person events, ¥93,500 long-hours plan (8 hours, weekends/holidays), and ¥5,000 × attendees complete package including catering. Used for seminars, study groups, networking events, and corporate meetings.
• Meeting Rooms Three private meeting rooms available for hourly rental: GalaxyRoom (¥2,000/hour, 4–6 person capacity, named by GalaxyBooks), 【ナダヤ】Leather Room (¥3,000/hour, 6–8 person capacity, named by leather manufacturer Nadaya), and 必ず楽しい部屋 (Kanaru Tanoshii Heya, ¥1,000/hour, 2–3 person capacity, named by HIRAKU). Equipped with web-conference microphones, speakers, and power strips.
• Virtual Office Service Business registration and address use service for entrepreneurs and small businesses needing a prestigious Osaka business address without physical office space. Starting at ¥5,500 per month.
• GRANDSLAM MEDIA Media platform showcasing stories of growth, co-creation, and connections through news, interviews, event reports, columns, and movie content sections.
• GRANDSLAM NFT Service NFT service providing digital collectibles for community members, launched in September 2023.
• GS TIMES (Video Series) Video series produced by GRANDSLAM featuring content about the community and events, with at least 7 volumes produced.

Quantifiable outcome

• 100+ events hosted on Peatix platform as of October 2024

Named customers1 record

Segments4 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

Six partnerships are on record, tiered core and minor.

• 株式会社アースメディア / 松本 淳coreStrategic or Co-development Partner · 1 November 2019Strategic partner met in November 2019 who has been part of GRANDSLAM's cooperative foundation from early stages.
• Flatier / 大村 和彦coreStrategic or Co-development Partner · 1 October 2019Early collaboration partner who met GRANDSLAM founder in October 2019 and established cooperative relationship from the beginning of the coworking space operations.
• GalaxyBooks株式会社minorOthersCompany that named the GalaxyRoom meeting space. The company's publications are displayed in the meeting room.
• 株式会社ナダヤminorOthersLeather goods manufacturer that named the 【ナダヤ】レザールーム meeting space. The company's leather products serve as decorative accents in the room.
• 株式会社HIRAKUminorOthersCompany that named the 必ず楽しい部屋 (Always Fun Room) small meeting space.
• 約35+ SponsorsminorOthersVarious companies listed as sponsors and supporters including TWINKLE STARS, Search Connect, Roufe, つなぐHR, ODK, Earth Media Corp, Foot Crown, ええエプロン, EIGHT, TSC Group, STYLE＝, LOGILESS, funholic, Ideal Recruit, 地域商人, K-AND, 町田社会保険労務士事務所, HiroPro, 場活動, PRIDES, HugShake, T's Sense, Mirai Marketing, hitoiru, decomaru, Life Session, MDNEXT, Kyoto Tax Accountant, Honmono All, Workaholic, NOBORDERS, 町学会, Pled, Metaben, TM-C, Recreat, Kokyufa, K-Noctua, Sales Marker, Commerce Media, and others.

Scale indicators6 records

Recent moves14 records

Expansion highlights4 records

Direct peers

• WeWork Japan: Global coworking leader with major Japan presence including Osaka locations. Directly competes with GRANDSLAM in the flexible workspace category, targeting freelancers, startups, and small businesses with daily and monthly memberships.
• instabase: Japan's largest event space marketplace allowing users to book hourly event and meeting venues. Directly comparable to GRANDSLAM's event space rental business model, particularly for small-to-medium group bookings.
• Space Market: Japanese marketplace for hourly event space and meeting room bookings. Competes with GRANDSLAM's meeting room and event space offerings via a broader supply of venues across Japan.
• TimeTicket: Japanese platform for booking spaces, meeting rooms, and professional services by the hour. Comparable to GRANDSLAM's hourly meeting room rental offering with similar target customers (freelancers, small teams).
• Bizcomfort: Japanese coworking chain offering 24/7 access, meeting rooms, and virtual office services. Competes with GRANDSLAM in the small-business and freelancer coworking segment with broader geographic coverage across Japan.
• H1T: Japanese coworking space operator with multiple locations targeting freelancers and small businesses. Comparable to GRANDSLAM in pricing structure (daily/monthly plans), customer segments, and community-focused positioning.
• IWG (Regus/Spaces): World's largest flexible workspace operator running Regus, Spaces, and HQ brands with significant Japan footprint. Competes with GRANDSLAM on coworking, meeting rooms, and virtual office services across major Japanese cities.
• fabbit: Japanese coworking chain with locations primarily in regional cities, often partnered with local governments. Targets similar startup and freelancer segments as GRANDSLAM with comparable community-building approach.
• Spacely: Japanese event space marketplace focused on hourly and short-term venue rentals for events, seminars, and meetings. Direct competitor to GRANDSLAM's event space rental business in the same Kansai and broader Japanese market.
• Co-ba: Tokyo-based community-focused coworking space with multiple locations (Shibuya, Jiyugaoka, etc.). Closely comparable to GRANDSLAM in community-driven positioning, member events, and design-forward space philosophy.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/grandslam_mp
• Facebookfacebook.com/grandslam2021
• Instagraminstagram.com/grandslam_official
• LinkedInlinkedin.com/company/grandslamofficial

Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about GRANDSLAM