US tax law offers powerful accelerated depreciation methods, Section 179 and Bonus Depreciation, allowing businesses to expense a large portion or even the full cost of assets in the first year. This contrasts sharply with Japan’s straight-line depreciation based on statutory useful lives. This article provides a comprehensive guide to US depreciation, detailing Section 179 and Bonus Depreciation, including eligibility, limits, calculation examples, pros and cons, common pitfalls, and FAQs, empowering businesses to optimize their tax strategies in the US.